Arsenal won 2-1 at West Bromwich Albion on Saturday to climb into the Champions League places at Chelsea's expense, while Aston Villa claimed a precious win in their fight to avoid relegation from the Premier League.
A brace from Tomas Rosicky gave Arsenal victory at The Hawthorns, but they allowed West Brom to come back into the game after Per Mertesacker was sent off for bringing down Shane Long in the penalty area.
James Morrison drilled the resulting penalty down the middle to reduce the arrears, but Arsenal held on to move into fourth place above Chelsea, who welcome Sunderland and their newly appointed manager Paolo Di Canio to Stamford Bridge on Sunday.
Rosicky proved his worth in the early stages of the game when he cleared a header from Claudio Yacob off his own goal-line.
In the 20th minute he distinguished himself at the other end, adroitly heading Gervinho's well-struck cross from the left past home goalkeeper Ben Foster.
The Czech Republic midfielder claimed his second five minutes into the second half, ramming home at the second attempt after Foster blocked his initial attempt from the edge of the box.
Mertesacker's mistimed lunge granted West Brom a lifeline that Morrison duly grasped with 19 minutes left, but Arsene Wenger's side survived a late onslaught from the home side as they closed to within a point of third-place Tottenham Hotspur.
"We now we have one target - to win our games," said Arsenal manager Wenger.
"Then we do not have to look at Tottenham or at Chelsea. If we lose our games, you have always to look at the results of the others."
Meanwhile, Matthew Lowton and Christian Benteke scored potentially crucial late goals to give Villa a 3-1 win at Stoke City that lifted Paul Lambert's team out of the relegation zone and drew the hosts into trouble.
Gabriel Agbonlahor converted at the near post from Lowton's right-wing cross to give Villa a ninth-minute lead, only for Michael Kightly to equalise for Stoke in the 80th minute.
However, with time running out, Lowton launched a magnificent 30-yard volley into the top-left corner in the 87th minute before Benteke added a third to send Villa three points clear of the bottom three.
Stoke, who have won just once in 13 games, are one point better off in 14th place.
"I don't think you will see a better goal in Europe, let alone anywhere else, than Matt Lowton's," said Villa manager Lambert.
"The technique, chest control, and volley was outstanding. He has played every minute of every game in the league and he has been outstanding.
"We are playing well. There is a lot of momentum there and collectively the players are doing fantastically."
Reading's hopes of avoiding relegation were seriously compromised after a 2-0 loss at home to manager Nigel Adkins's former club Southampton left them eight points from safety with only six games remaining.
Despite sustained early pressure from Reading, Southampton took a 34th-minute lead through Jay Rodriguez and completed victory with 18 minutes remaining when captain Adam Lallana coolly tucked away his 50th goal for the club.
Reading thought they had pulled a goal back moments later, but Saints goalkeeper Artur Boruc was adjudged not to have carried Adam Le Fondre's header over his own goal-line in what was a very marginal call.
Adkins joined Reading last month after Southampton sacked him in January, but his bid to steer his new club off the foot of the table is beginning to look like an impossible task, particularly as the Royals have now played at least a game more than the three teams immediately above them.
"We needed a win today," Adkins said. "We were up against a good team but we're at home and we've got to win the game of football. We've not done that, that's the reality of where we are. We've got to keep working hard."
Southampton, meanwhile, are now seven points above the bottom three after their third consecutive victory and appear poised to secure their status among the elite for a second season.
Elsewhere on Saturday, Norwich City were denied only a second win in 15 games in an entertaining 2-2 draw at home to Swansea City.
Norwich came from behind to lead through Michael Turner after Robert Snodgrass had cancelled out Michu's 35th-minute opener, but Luke Moore headed in a 75th-minute equaliser to prevent Swansea from slipping to a fourth straight defeat.