Chelsea roared back from two goals down to beat Tottenham 4-3 on Sunday, moving just four points behind Premier League leaders Liverpool after Arsenal were held by Fulham.
The Gunners and Chelsea both started the day seven points adrift of Arne Slot's side, whose game this weekend was postponed due to stormy weather.
Arsenal were forced to settle for a 1-1 draw but Enzo Maresca's Chelsea, kicking off later Sunday, mounted a stunning comeback at the Tottenham Hotspur Stadium.
Dominic Solanke and Dejan Kulusevski put Spurs two goals up inside 11 minutes but Jadon Sancho quickly pulled one back with a fine strike and the second half belonged to the visitors.
Cole Palmer equalised from the penalty spot in the 61st minute and Enzo Fernandez put Chelsea ahead 12 minutes later.
Palmer's ice-cool "Panenka" spot-kick gave the visitors a two-goal cushion before Son Heung-min added a late third for Spurs.
Second-placed Chelsea now have 31 points after 15 games, two points ahead of London rivals Arsenal. Liverpool, with a game in hand, are on 35 points.
"The plan or the idea is to not let the players slow down," Maresca told Sky Sports. "They cannot drop because they know another player is waiting to come in."
But the Italian, in his first season at Stamford Bridge, played down his team's title chances.
"Arsenal, Manchester City and Liverpool probably don't slide like what Cucurella did," he added. "To be serious, we are not ready – we are far from these teams, but we focus on day-by-day and trying to improve the team."
The defeat is a disastrous result for under-pressure Spurs boss Ange Postecoglou, whose side hammered champions Manchester City 4-0 just two weeks ago.
"It is a sore one, a painful one," said the Australian, whose team are now 11th in the Premier League table after their seventh defeat.
Earlier, Bukayo Saka had a late winner ruled out for offside by a VAR review as the Gunners' four-match winning streak was halted in west London.
Raúl Jiménez fired Fulham into an early lead before William Saliba levelled after yet another Arsenal goal from a corner.
"We are very disappointed not to win the game – overall we absolutely dominated the game from start to end," Arsenal boss Mikel Arteta said.
"We did all the things that we wanted to do during the game and unfortunately we concede one goal in one shot. The way the team played, the way the team wanted to win, it was unbelievable."
Arsenal were still without influential defensive pair Gabriel Magalhães and Riccardo Calafiori through injury and Fulham exposed a makeshift left side of the Gunners' backline to take the lead.
Arsenal underlined their threat from set-pieces when they scored twice from corners to beat Manchester United 2-0 in midweek. (AFP)