Petr Cech believes Chelsea's record for the fewest goals conceded in a Premier League season is "impossible" to break, after Arsenal failed to do so.
Back in 2004-05, under Jose Mourinho, Chelsea set the incredible record of just 15 goals conceded across a Premier League season.
Cech was in goal for that remarkable campaign, keeping 24 clean sheets, another record in the competition's history, as he faced 83 shots on target overall.
Arsenal had been tipped as candidates to break the record, and it looked under threat when they conceded just five goals in their first 11 matches of the campaign.
However, they have kept just five clean sheets in the following 13 matches, and they have now conceded 17 goals for the season, surpassing Chelsea's total in their 3-2 defeat to Manchester United.
Arsenal have faced 16.4 expected goals against (xGA) this term, underperforming their total slightly. They have faced 185 shots in total, with 50 of those on target.
"Well, I think this season actually showed how impossible it [the record] looks because, you know, after 10 games, I got a lot of questions about it," he told ESPN Brasil.
"And I said, 'well, I think it's going to be hard for them to do it', but they were doing so well that actually they gave themselves a chance.
"So, 10 games in, you think, 'Oh, they have a big chance'. Then, 15 games in, you just go 'hmm, I don't think they can do this'.
"And now we are [here] after 21 games or whatever it is, and the record's gone. So, it just shows you how difficult it is to not concede in the Premier League.
"You have to play well, you have to be organised, you need a bit of luck, and everything comes together, and you play difficult opponents as always.
"So, it's not an easy task, and I think this season was the first time we were kind of looking at it and thinking: 'They might be close', and they are not.
"So, it just shows you how incredible the record is."
Cech won four Premier League titles with Chelsea between 2004 and 2015, when he crossed London to join the Gunners, winning his fourth Golden Glove in his first season at the Emirates Stadium.
The only teams in the last 10 years that have come close to Chelsea's total were Liverpool (22 goals conceded) and Manchester City (23), both in 2018-19.
Cech highlighted what made the 2004-05 Chelsea side so special, saying: "I think it came from the system and from the personalities as well.
"Because we suddenly realised that winning 1-0 gives you a chance to win the title, and we were kind of proud to be the team that was hard to beat.
"So, you could feel every single player on the pitch trying to do their best to give a bit of work defensively to help the defenders, and obviously me, as a goalkeeper, not to be constantly under pressure.
"And we had some fantastic players as well in the defensive line with [Claude] Makelele sitting in front. And of course, it's a huge help.
"But it's not only about the five defenders and the goalkeeper, it is about the team, how well you help each other.
"And I think it came from Jose, who made us understand that being the team that is hard to beat and defends well gives you the best chance to win the league, and this is what we did."