Klopp's Coutinho vision for Liverpool and what it might have looked like

Coutinho scored a hat-trick and Liverpool hit seven goals less than a month before he forced a move away from Anfield.

It was a day when everything clicked for Liverpool.

Seven goals hits the back of the net for the Reds for the second time in the Champions League group stage and Jurgen Klopp's new front three were firing.

Indeed, Mohamed Salah, Roberto Firmino and Sadio Mane were all on the scoresheet for the third time that season, but none of hogged the headlines the next day.

That honour went to Philippe Coutinho, who scored a hat-trick for the only time in his Liverpool career.

It was a significant day for the Brazilian, who also captained Liverpool in the absence of Jordan Henderson, and he set the tone with a penalty inside four minutes.

The second goal followed within 15 minutes and it was a beauty. Mane and Salah combined to find Firmino, who set up Coutinho to score.

Then the floodgates opened.

Firmino added a third after Mane caught Spartak napping. Mane added one himself - with the goal of the game no less - before Coutinho completed his hat-trick. Mane got his second and Salah wrapped it up in the dying embers.

Spartak were left shellshocked.

It was liquid football and underlined just how good Liverpool could be when Klopp's side put it all together.

And Coutinho was at the very heart of it.

Playing off the left in what was a very unorthodox 4-4-2 formation, the little Brazilian was given licence to roam further forward and join Salah and Firmino in attack. Mane did likewise from the right as Gini Wijnaldum and Emre Can sat deep.

It's not a formation Klopp has used on a regular basis, but it helped completed overwhelm Spartak.

Granted, the Russians weren't the stiffest of competition - they had lost 23 of 29 away games in the Champions League - but this was a Liverpool side without the signing of Virgil van Dijk, Fabinho or Alisson Becker.

Klopp's tactics do give us a potential glimpse into what life could have been like if Coutinho had stayed at Anfield.

The Reds were able to improve by using the £142m fee to bring in Van Dijk and Alisson, but Klopp had always maintained he didn't want to have to sell Coutinho and the Reds had planned for the signing of Van Dijk before any acceptable bid from Barcelona had materialised.

It's easy to forget that prior to leaving Anfield, Coutinho was in the form of his Liverpool career. He had been directly involved in 15 goals in 11 appearances, including the Spartak game - and he'd scored nine of them.

In total, Coutinho had 70 touches inside Spartak's half during the victory, dominating the pitch on the left hand side and linking Wijnaldum and Can with Liverpool's attack.

Such was Coutinho's skillset, Klopp changed his system to get the best out of him along with the devastating front three.

If Coutinho were still at Liverpool now, you can imagine him taking up that position with a midfield combination of Fabinho and Henderson anchoring the midfield.

The issue, of course, would be that Liverpool's full-backs simply couldn't get forward like they do when Klopp plays with three in the middle, and who's to know how Liverpool would have developed as a side should Coutinho have stuck around.

What's certain, is it'd be another exciting option for Klopp to call on.

Sadly for Liverpool, the night would only offer a tantalising glimpse into what could have happened. Coutinho would score three more times before a 'back injury' struck ahead of the New Year's Day trip to Burnley.

He'd never play for Liverpool again.

We'll never know whether Klopp's side would have made the great strides they have done without the now-Bayern Munich man, but he did play his part in what is Liverpool's second biggest home victory of the Champions League era.

A win that put Liverpool into the knockout phase but more importantly, put Klopp's men on the European map once again.

Eighteen months later and Liverpool were European Champions. Coutinho could only wonder what might have been.