ARSENAL'S 2-2 draw with Liverpool really was a game of two halves - both in terms of the scoreline and in terms of tactics.
Mikel Arteta's Gunners came out on top in the first 45, going in at the break leading 2-1.
Bukayo Saka and Mikel Merino scored either side of Virgil van Dijk's header.
But genius Arne Slot delivered a masterclass in the second half to get the Reds back into it.
And he got his reward when Mo Salah fired in the equaliser late on as it finished honours even.
SunSport's tactical guru Dean Scoggins broke down all the tactics and tricks from the Emirates in the latest episode of Tactics Exposed...
1. ARTETA BAMBOOZLED SLOT'S DEFENCE
It was the way Arteta decided, 'We're going to make the pitch massive.'
And that's a surprise against Liverpool because we know how good they are at covering ground.
And we've talked before about their 4-2-4 press and how the monsters in midfield really go for it. But basically, with Thomas Partey playing at the back for Arsenal, as we expected him to do, that also meant that Rice and Merino had an enormous amount of ground to cover.
But Arteta's backed them to do it and they've done it.
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But the really intriguing thing came with what they did with Leandro Trossard and Kai Havertz.
Never mind false nine, this was no nine. No nine whatsoever.
It was really strange that Ibrahima Konate and Van Dijk took quite a long time, as did the Liverpool midfield and the Liverpool dugout, to work out what was happening here.
Havertz was drifting out to the right-hand side. His touch map for basically the whole game was effectively inside right, which meant him and Saka were doubling up down that right-hand side.
Then on the left-hand side, Trossard was going over to where Gabriel Martinelli was.
There were occasions where when they were lined up, Trossard and Havertz were actually in line with their own full-backs, where Partey was pushing up one side and Jurrien Timber was pushing up the other. Then you've got your strikers, who are not really strikers, in that line.
That was because of what we talked about before in creating that space behind the Liverpool back four. But also it made this enormous gap.
So Alexis Mac Allister, Curtis Jones and Ryan Gravenberch got a bit lost in midfield.
Are they sitting in front of their back four for no reason because there's no strikers there? Or are they going, 'OK, we'll follow them out wide', which means there's this enormous gap down the middle. Or do we gamble and go?
They got a bit stuck in between all those things. And so did Van Dijk, so did Konate.
But you've got to give kudos to the Arsenal midfield too.
Merino and Rice, the ground that they covered was just phenomenal.
That's Declan Rice's best performance since well before the Euros. He was fabulous. And in a two with Merino to the left and him to the right, they dominated that first half.
2. HAVERTZ'S UNSEEN ROLE FOR SAKA GOAL
Havertz was doing this move to the right-hand side.
The defender wants to mark. Van Dijk and Konate want to go head-to-head with their man. They want to win the duel. They love 50-50 duels and that's what they want.
Obviously it was an instruction from Arteta but Havertz just went over to that right-hand side and it did two things.
First of all, it meant that Liverpool pushed up and left that space in behind because they felt they could.
And also because, not as often as I thought they might, they went direct from David Raya.
But what they did more often was play into the full-back areas where Ben White played the pass from originally and also from the other side.
But what it means again is Liverpool push up slightly. And then Havertz and Saka are almost looking at each other. And you can see in the build-up to the goal, Saka's pointing to Ben White because it's the moment.
It actually happened on four minutes and they didn't quite score because the pass was over-hit. That should have been the warning for Liverpool, for Andy Robertson and Van Dijk, that this is what they're trying to do. They're bringing us up.
You would think, why are they distracted by Havertz? Why are they bothered about him?
It's simply because he's neither deep enough for a midfield player to pick him up, but he's not high enough for a centre-back to pick him up.
He's in this no-man's land in between.
All he's doing is doing it for his mate Saka. Ben White hits this gorgeous pass over the top. What a pass that was.
Obviously, Saka's still got a lot to do and it's an absolutely sensational finish.
But one thing I spotted as well in the replays after the goal was that Ben White goes up and taps Havertz on the face and congratulates Havertz because they know that that's the plan before the game.
They just did it brilliantly.
Kai Havertz is this tactical genius and for Germany, he does it as well.
For Germany, he often plays in different positions. He's played left wing-back. He plays inside left. He plays off the front and he's played the front man as well.
These managers, these tactical groups of coaches know that Kai Havertz can do exactly the role that they want to do.
3. LIVERPOOL'S CORNER KICK TRICKS
Mac Allister and Luis Diaz out-Arsenal'd Arsenal. It's normally Ben White doing it at the other end, fiddling with goalkeepers' gloves or getting in the way of people.
But this time he got done by Mac Allister. You're expecting Arsenal to want those collisions in a six-yard box and dominate those collisions.
Liverpool did it with two of the players who you wouldn't expect to dominate.
Luis Diaz makes this fabulous run from inside the goal to the front post for the flick-on. Arsenal don't communicate well enough.
But what Mac Allister does is he leans on his man, who's Ben White, and he's just holding him. It's not a foul, as we've seen time and time again with Arsenal.
He creates chaos and it should be Ben White who clears up after the flick. He doesn't because he's more concerned about Mac Allister, then it goes through to Van Dijk.
They did it slightly earlier as well, again, Liverpool. So there was another warning for Arsenal there. They didn't heed it.
Van Dijk flicked on the first one, this time it was Diaz. So Liverpool have worked on two or three variations of the same thing.
Van Dijk's very strong at the back post. Partey does lose him a little bit.
Credit to Liverpool and to Mac Allister because he carries out his little dirty role in there perfectly.
Set pieces in the Premier League at the moment. It's so key.
Tony Pulis and Sam Allardyce must be thinking, 'Well, when we did it, lads, nobody gave us any credit for it. They just said we were route one.'
4. 'MIND THE GAPS' SET-PIECE TECHNIQUE
Arsenal are lining up with four or five players at the back post, all in offside positions. So not offside because the ball's not being played but in offside positions.
Then as Declan Rice puts his hand up - let's give him credit for the sensational delivery - the four or five players move into the line and then come back in between the Liverpool players into onside positions.
That does two things. One, obviously you're onside. Two, it creates collisions. And so because they're bouncing off each other, it also means the Arsenal players are going towards the goal and the Liverpool players are going away from the goal.
They did it twice. Merino actually should have scored before then. I think it actually was Partey who blocked him because it was so chaotic in there.
Liverpool had a couple of warnings to sort it out, and they didn't sort it out.
They can do this by just stepping up. And that's very difficult to think about in a game situation. But they have got Virgil van Dijk there.
They should have got a message on, especially after the second one.
But what Arsenal do is obviously very clever because it creates two things.
It creates that thing about offside. But the uncertainty it creates as well is because if those two groups of players come together in between each other, who are you picking up as a defender? You don't really know.
What Arsenal actually got right was they put two players in between two Liverpool players instead of one.
Instead of it alternating in a line, on the goal they put two players in between, which means if Konate's picking up the first man, he can't pick up the second one and then the next Liverpool player's got his back to him.
That was when Merino scored.
It was genius by Arsenal. But I would like to think that Liverpool have a chat and step up to give them four more yards to get to the edge of the box, four yards further away from the goal.
Because then they'd almost have to run out to get back onside by the time Rice kicked it. And then also they're further away from the goal.
It is fascinating to watch.
Set pieces are such a massive part of the game now.
And one of the Liverpool problems in the first half that shouldn't be overlooked as well was the number of fouls that they made. They kept giving them free-kicks in those areas.
5. SLOT'S MIDFIELD SWITCH TO SAVE THE GAVE
The focus here should be on Slot. It wasn't actually at half-time that they made the switch, Dominik Szoboszlai came on around the hour mark.
But at half-time, they definitely made a move where Curtis Jones wasn't playing as a No10 anymore, he was playing on the right of the three so that Mac Allister and Gravenberch had a bit more help when Trossard and Havertz dropped in and when Merino and Rice pushed on.
Because Arsenal made the pitch so big and the midfield area so large, Jones was sort of caught between. Am I the second striker?
Darwin Nunez gets through so much work, he was coming back into that midfield zone as well, which on one hand is huge credit and on the other hand is, 'Mate, just stay up front and lead the line.'
Liverpool sorted that out at half-time. Nunez led the line much better and Jones started in his position.
But it was when Szoboszlai came on. Trent Alexander-Arnold and Szoboszlai have got this really, really great understanding.
Szoboszlai was on the field about 35 seconds and Trent was already playing centre midfield. He just went and played in there, knowing that Szoboszlai's got the legs and the sense of mind to be covering him going back the other way.
They also took a risk that Martinelli was very tired. Timber was patched up to play and then obviously got taken off.
But all of a sudden Alexander-Arnold was picking the ball up in those central-midfield areas again. Szoboszlai was stretching the game in both directions.
I get the impression that at 2-1, Liverpool felt like they had enough to get back in the game and score the goal. In the end, they were probably disappointed they didn't go on and win the game.
Because as dominant as Arsenal were in the first half, there was a period from when Szoboszlai came on until about the 80th minute where it was one-way traffic.
All of a sudden Trent was dictating play from midfield. He hit a couple of poor passes before his fabulous pass for the goal.
Because he was now occupying this space where he knew Szoboszlai was there for a little bounce pass, give and go.
Szoboszlai was covering him as well and then he was freed up to go and play.
So credit there to Arne Slott again. Credit there to Szoboszlai - he knew exactly what he's being asked to do and he carried it out perfectly.
From a tactics perspective, I think it was a mistake not to start Szoboszlai.
But Curtis Jones had played so well the week before. How do you leave him out? And Gravenberch and Mac Allister have been so, so good all season. It's a nice problem to have.
It came down to a couple of pieces of genius to get the equaliser.
Trent's pass over the top then the quality of Salah and the IQ to know from the pass he was offside then to loop round the back of Nunez for the second pass.
There's not many players who late on in an intense game - and he'd been very frustrated a few times before - would have that state of mind and calmness in that situation.
Then obviously the finish at the end, is really, really high-level stuff.