Analysis of Saturday's London derby from Stamford Bridge, with the help of Stats Zone.
1) Zouma's the man to replace Terry
When John Terry was left out of Chelsea’s starting XI for Wednesday evening’s Champions League tie with Maccabi Tel Aviv, popular wisdom was that he was merely being rested and would return to the team against the Gunners.
However Jose Mourinho instead opted to start Kurt Zouma alongside Gary Cahill, and it was a move that certainly paid dividends - and not just because he scored the game’s opening goal.
The Frenchman’s pace was also a particular boon for the previously struggling champions, and his speed helped the Blues quell the threat of Theo Walcott. This was particularly evident in the 38th minute, when Walcott was played through, only to be caught and dispossessed by the 20-year-old. Had it been Terry in the same scenario, it’s hard to imagine the Arsenal man would’ve been denied the chance to get a shot at goal.
As well as scoring the crucial first goal, Zouma made 3 tackles, 2 clearances and won all 3 of his aerial duels. Zouma's performances last season hinted that he could one day be JT's heir. Perhaps that day has come. Whether it’s Stones or Terry, Zouma’s performance was enough to raise the question ‘John who?’
2) You can't get sucked in to Costa’s game
There have been few players in English football's recent history as determined to get involved in hot-headed shenanigans as Diego Costa. There have also been very few players so adept at riling opposition players and fans. The key for anybody without Chelsea's best interests at heart is not to stoop to his level.
"He can do what he wants, and he stays on," Arsene Wenger said of the Brazilian-come-Spaniard after the match. "He will do same next week, and week after, and get away with it."
And that's kind of the point. Costa has a knack of avoiding the full wrath of Premier League referees - there's a certain level of underhand skill involved. You almost have to respect him for it. Almost.
The players who try to play him at his own game often aren't quite so lucky. They aren't masters of the craft. They aren't so clever. Enter Arsenal defender Gabriel Paulista.
Costa may have put three hands in Laurent Koscielny's face (not all at the same time, obviously) and chest-barged the French defender, but evidently not while referee Mike Dean was watching.
Gabriel swung a backheel at Costa right under the ref's nose, and was promptly shown the red card. Yes, Costa should also have been sent off, but the foolish Gabriel can have no complaints about his own dismissal. A statistic that Arsenal fans won't enjoy, but Chelsea fans certainly will - Costa wasn't penalised for a single foul during his 82 minutes on the pitch.
3) Hazard is starting to warm up
Chelsea's slow start to the season hasn't been down to any one player - many of last season's stars failed to get near matching last season's performance levels in the early weeks of 2015/16, with Eden Hazard among them. But the signs are that the Belgian is finally starting to click onto gear.
The 24-year-old was back to somewhere near his creative best against Arsenal - he made more attacking third passes than any other player (45), created more chances then any other player (5), and dribbled past more opponents then any other player (8). He rounded off in injury time by scoring his first goal of the season. It wasn't 'vintage' Hazard, but it was certainly something a lot more like it.
4) Chelsea have Arsenal's number
The Blues are now eight Premier League matches unbeaten against their London rivals, their last defeat coming in October 2011, when Andre Villas-Boas' Blues were beaten 5-3. Chelsea have kept six clean sheets in their last eight league matches against the Gunners, including the last five in a row.
Arsenal have now gone 482 minutes without a goal against the current champions. Eden Hazard has scored in his last three home Premier League matches against Arsenal, while Cesc Fabregas has provided an assist in both of his meetings with his former club at Stamford Bridge.
All of which brings us on to...
5) Arsene must do better
The kerfuffle around handshakes (or lack of them) is sign enough that Arsene Wenger doesn't enjoy meetings with Jose Mourinho, but this is just too much. In 15 matches against his Chelsea counterpart, Wenger has lost 8, drawn 6 and won just once - last month's Community Shield triumph at Wembley.
Tottenham Hotspur, Newcastle United, Everton, Crystal Palace, Sunderland and Middlesbrough have all enjoyed more victories over Mourinho than Arsenal have mustered down the years. Even League One outfit Bradford City have managed to beat him the same number of times.