Arsenal's thrilling derby win over Tottenham continued the theme of their season, with another stirring second-half comeback inspired by their substitutes.
Trailing 2-1 at the interval against their north London rivals, the Gunners roared back to win 4-2 as Alexandre Lacazette stepped off the bench to score and fellow replacement Aaron Ramsey claimed the assist for Pierre-Emerick Aubameyang's second goal.
Here, Press Association Sport looks at the figures behind Unai Emery's team and their in-game improvements.
Half-time table makes grim reading
Remarkably, a league table based on only the first halves of games this season shows the Gunners in 19th place, one of only two teams without a win.
Ten of Arsenal's 14 games have been level at half-time while they have trailed in the other four, against Manchester City, Crystal Palace, Wolves and Spurs.
City doubled their lead to 2-0 to inflict one of only two defeats this season on Emery's side but the other three fixtures brought two draws and Sunday's win.
Cardiff are the only other club not to have led at half-time, leaving them bottom of that notional table, while Fulham occupy the final relegation place having trailed in eight games. Burnley would be outside the drop zone on goal difference.
Manchester City's unbeaten record would be intact but Liverpool would drop three points back, having been 1-0 down to Chelsea at the break before snatching a point with Daniel Sturridge's late stunner.
Crystal Palace jump eight places to sixth – one behind Bournemouth, who are five places better than their real position – while Everton drop seven to 13th.
Emery's changes pay dividends
Goals from substitutes have been a key reason for Arsenal's resurgence in the second halves of matches, with Aubameyang to the fore.
The Gabon striker has rotated with Lacazette in the centre-forward position, allowing Emery to make changes and use the pair in tandem should the need arise.
Illness kept Aubameyang on the bench against Fulham in October but he came on to score twice in just under half an hour of action, before repeating the feat against Leicester two weeks later.
Fellow substitute Ramsey also netted against Fulham while Danny Welbeck and Henrikh Mkhitaryan achieved the feat against West Ham and Wolves respectively.
Lacazette's derby-day contribution edged Arsenal's substitutes ahead of Chelsea's, who have contributed seven goals this season after Ruben Loftus-Cheek's second such strike earlier in the day against Fulham. Pedro, Willian, Alvaro Morata, Ross Barkley and Olivier Giroud have also scored as substitutes.
Liverpool and Manchester United have four goals apiece from their replacements, Sturridge and Marcus Rashford both doubling up, while Burnley, Everton, Leicester, Manchester City and Newcastle have three apiece.
Brighton, Palace, Fulham, Huddersfield, Southampton and Watford have yet to get a goal from a substitute this season.
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