Arsenal preserved their lead in the Premier League by beating Fulham 2-0 on Saturday, while goal-line technology assisted Manchester City as they overcame Cardiff City.
Arsenal knew that anything less than victory might allow City to gazump them, but it was not until Santi Cazorla claimed a quick-fire brace mid-way through the second half that they put paid to Fulham at the Emirates Stadium.
Fulham goalkeeper Maarten Stekelenburg had frustrated Arsenal in the first half, but he was beaten in the 57th minute when Cazorla slid a shot past him after a neat interchange involving Olivier Giroud and Jack Wilshere.
The Spanish midfielder added a second five minutes later, collecting the ball on the edge of the box after Nacho Monreal's cross was partially cleared and drilling a low shot into the bottom-right corner.
"The players were conscious we had to step up a gear," said Arsenal manager Arsene Wenger.
"It was just a question of time and Santi Cazorla delivered two special goals."
City remain a point behind Arsenal after sinking Cardiff 4-2 on a day of milestones at the Etihad Stadium.
Edin Dzeko broke the deadlock in the 14th minute with a goal that was City's 100th of the season and appeared to represent the first time that goal-line technology has been decisively used to award a goal in the Premier League.
The Bosnian striker's miscued effort from David Silva's pass was hacked away from beneath the crossbar by Aron Gunnarsson, but Hawkeye replays shown on the stadium's video screens confirmed that the ball had just crossed the line.
Craig Noone equalised in the 29th minute after exploiting slack defending from Martin Demichelis and Vincent Kompany, but Jesus Navas restored the hosts' lead four minutes later with a measured finish.
Yaya Toure added a third goal in the 76th minute after a one-two with Sergio Aguero, who got on the score-sheet himself three minutes later to claim his first league goal since returning from a calf injury.
Fraizer Campbell pulled a goal back late on for Cardiff.
"Maybe I am not 100 per cent happy because we conceded the second goal in the last minute," said City manager Manuel Pellegrini.
"But we scored four and missed five or six clear chances, so if we continue to play like we are, we are always going to score more than we concede."
Liverpool fought back from two goals down to record a 2-2 draw at home to Aston Villa, but squandered an opportunity to close on third-placed Chelsea, who host Manchester United on Sunday.
Surprise victors at Anfield last season, Villa opened up a 2-0 lead inside 36 minutes after Andreas Weimann tapped in Gabriel Agbonlahor's cross and Christian Benteke exploited an error by Simon Mignolet to head home.
However, Daniel Sturridge equalised in first-half injury time, stabbing home from Jordan Henderson's flick, before Steven Gerrard equalised with a 53rd-minute penalty after Villa goalkeeper Brad Guzan felled Luis Suarez.
The draw left Liverpool eight points behind Arsenal and three points shy of Chelsea, while they are also at risk of being overtaken by city rivals Everton, who visit West Bromwich Albion on Monday.
Southampton were denied a morale-boosting victory after Sunderland also hit back from 2-0 down to record a 2-2 draw in an engaging encounter at the Stadium of Light.
Despite being rocked by the resignation of chairman Nicola Cortese on Wednesday, Southampton took control through Jay Rodriguez and Dejan Lovren, only for Fabio Borini and Adam Johnson to earn Sunderland a point.
Yohan Cabaye scored twice as Newcastle United bolstered their challenge for European qualification with a 3-1 success at West Ham United, who slipped into the bottom three.
Jason Puncheon catapulted Crystal Palace out of the relegation zone after atoning for a woeful penalty miss at Tottenham Hotspur last weekend by scoring the only goal in a 1-0 win over Stoke City.
Elsewhere, Ryan Bennett scored in the 87th-minute to give Norwich City a precious 1-0 win at home to Hull City, who had Tom Huddlestone sent off for two bookable offences.