Chelsea weathered an extraordinary 65-yard goal by Charlie Adam to re-establish their seven-point lead at the Premier League summit with a 2-1 defeat of Stoke City on Saturday.
Arsenal had trimmed Chelsea's lead to four points by blitzing Liverpool 4-1 and a twist appeared in store when Adam cancelled out Eden Hazard's 39th-minute penalty in show-stopping fashion at Stamford Bridge.
A minute before half-time, the Scottish midfielder picked up a loose ball deep inside his own half and launched a raking shot with his left foot that Chelsea goalkeeper Thibaut Courtois could only help into the net.
It was a goal that brought to mind David Beckham's famous lob against Wimbledon in 1996 and Chelsea's cause was further harmed when Diego Costa limped off with a hamstring injury 10 minutes after coming on at half-time.
But Loic Remy gave Chelsea victory in the 62nd minute, tapping home a pass from Hazard after Willian had intercepted Asmir Begovic's throw, to leave Jose Mourinho's side seven points clear with a game in hand.
"Every victory is one step ahead," Mourinho told the BBC. "The others know they have to win every game. For us, we have to think about ourselves and forget about the others."
Mourinho, who described Adam's strike as a goal "every super player in the world would like to score", said that Costa would be out for a "minimum" of two weeks.
Arsenal had earlier dealt Liverpool's Champions League qualification hopes a massive blow with a stylish victory that lifted Arsene Wenger's side to second place.
Arsenal scored three times in a dizzying eight-minute spell immediately prior to half-time at the Emirates Stadium, with Hector Bellerin, Mesut Ozil, from a direct free-kick, and Alexis Sanchez on target.
Jordan Henderson hit back with a 76th-minute penalty, but after Emre Can was sent off for two bookable offences, Olivier Giroud slammed home Arsenal's fourth in stoppage time.
"It was a very great day," said Arsenal manager Wenger. "It was an important game today. We had the chance to make a difference with Liverpool and we took the chance."
Beaten 2-1 by Manchester United before the international break, Liverpool have now lost twice in succession and were left seven points below the top four after United beat Aston Villa 3-1.
- Rooney stunner -
Liverpool manager Brendan Rodgers admitted that it would be "very, very difficult" for his side -- previously unbeaten in 13 games -- to secure a place in the top four and return to the Champions League.
"It was a game we needed to take something from," Rodgers told BT Sport. "Today is a big disappointment, but we didn't defend well enough in key moments of the game."
Champions Manchester City slipped to fourth place ahead of their trip to Crystal Palace on Monday after United sank Villa at Old Trafford to claim third place and move eight points clear of Liverpool.
Ander Herrera scored twice for the hosts and Wayne Rooney found the net with a stunning shot on the turn, while Christian Benteke replied for Villa with a tame effort that crept underneath David de Gea.
"We are still not certain about Champions League qualification -- it is still a rat race," said United manager Louis van Gaal, whose side have won five games in a row.
"But we have given a blow to Liverpool and Southampton also lost. It is a big gap. Now we have to wait to see if the gap is too big for Tottenham, too."
While Tottenham Hotspur, a point behind Liverpool, visit Burnley on Sunday, sixth-place Southampton spurned a chance to break into the top five after Phil Jagielka's 16th-minute goal saw them beaten 1-0 at Everton.
Meanwhile, Queens Park Rangers and Leicester City both improved their chances of avoiding relegation with victories, the former winning 4-1 at West Bromwich Albion and the latter beating West Ham United 2-1.
Eduardo Vargas, Charlie Austin, Bobby Zamora, with an exquisite lob from wide on the right, and Joey Barton scored for QPR at The Hawthorns, with substitute Victor Anichebe heading in a consolation for West Brom.
QPR are now a point behind fourth-bottom Sunderland, while bottom club Leicester closed to within four points of safety after Andy King's close-range 86th-minute strike saw off West Ham.
In the day's other game, Bafetimbi Gomis scored twice to earn Swansea City a 3-1 win at home to Hull City, who had David Meyler sent off for a reckless foul on Kyle Naughton.
Source: AFP