Liverpool moved to within six points of winning the Premier League as they bounced back to beat Bournemouth, while Manchester City slipped to another defeat at Manchester United.
Derby delight for the Red Devils kept them on Chelsea's coattails in the battle for a top-four finish, but it was also a good Sunday for the Blues as they thrashed Everton 4-0.
Here are three things we learned from the Premier League weekend:
United revival for real
United are now unbeaten in 10 games in all competitions, including two wins over City and a 2-0 victory at Chelsea.
The arrival of Bruno Fernandes towards the end of the January window has made a massive impact in midfield, but it is at the back Ole Gunnar Solskjaer's men are most improved in recent months.
City were kept at arm's length for an eighth clean sheet in that 10-game run, with Harry Maguire and Aaron Wan-Bissaka beginning to repay the big transfer fees splashed on them in the summer. David de Gea was more like his old self in goal after a costly error at Everton last weekend.
Plenty of work still needs to be done to secure a return to the Champions League, either via the Premier League or Europa League, but for the first time since Solskjaer was appointed on a permanent basis a year ago, United are going in the right direction.
Chelsea take control
What a difference a week has made for Chelsea boss Frank Lampard as his side cemented their place in the top four with a swaggering 4-0 rout of Everton.
Just eight days ago, the Blues needed a late equaliser just to escape with a draw at lowly Bournemouth -- a dispiriting result on the back of their Champions League last 16 first leg humiliation against Bayern Munich.
For the first time in his reign, the critics were sharpening their knives for Lampard after a run of five wins in 16 Premier League games.
But Tuesday's FA Cup fifth round win over Liverpool lifted the mood at just the right time and Chelsea followed that with an even more emphatic result against Everton.
Teenager Billy Gilmour pulled the strings again in midfield to win man of the match for the second time in a week, but three of Lampard's more senior players stood up to be counted as Pedro, Willian and Olivier Giroud found the net after Mason Mount's opener.
Chelsea's biggest league win of the season puts them firmly back in control of the chase for a place in next season's Champions League.
United kept the gap between the two at three points, but Lampard's men now enjoy a five-point lead over Wolves with fifth possibly enough due to City's two-season European ban, which is pending an appeal to the Court of Arbitration for Sport.
Liverpool steady the ship
Liverpool's remarkable consistency in romping towards a first league title in 30 years made a series of defeats in three different competitions in recent weeks seem like a slump.
The Reds bounced back by coming from behind to beat Bournemouth 2-1 on Saturday to move within two wins of clinching the title.
There were still some concerns for Jurgen Klopp ahead of Wednesday's Champions League last 16 second leg against Atletico Madrid, where Liverpool must come from 1-0 down to progress.
Adrian looked unsure in goal in the absence of the injured Alisson Becker and up front Roberto Firmino is yet to score at Anfield this season.
But rediscovering the winning feeling felt much more special after a couple of weeks out of that routine.
"There's nothing good in losing football games but it makes you aware of how special it is to win football games," said Klopp.
"That's what we had in the last 10 days or two weeks when we lost games. So you appreciate it much more."