Chelsea manager Frank Lampard enjoyed a memorable win over his former Blues boss Jose Mourinho as his side beat Tottenham Hotspur 2-0 in a fiery London derby overshadowed by racism allegations, while Manchester United again succumbed to one of the Premier League’s lesser lights as they lost 2-0 to bottom-of-the-table Watford.

Liverpool remained 10 points clear at the top of the table without playing a match – they won the Club World Cup for the first time thanks to a 1-0 victory over Brazilian side Flamengo in Doha on Saturday – when second-placed Leicester lost 3-1 to Manchester City.

Here’s a look at three things we learned from the Premier League weekend

Lampard comes of age

After four defeats in their previous five league games, Chelsea made the short trip across London to face Tottenham beset by doubts for the first time in Lampard’s debut season in charge.

That run stoked fears about Lampard’s lack of experience in just his second season as a manager, with Chelsea fans hoping he could steer them back to the glory days he enjoyed as a player.

But Lampard gave the perfect response, fittingly against the manager who was his mentor when he shone in Chelsea’s midfield.

Changing from his usual 4-3-3 formation to a 5-2-3 system, Lampard completely out-witted Mourinho, who was powerless to counteract the switch as Willian’s double confirmed Chelsea will spend Christmas Day in a morale-boosting fourth place.

United struggle with the ball

Manchester United are a Jekyll-and-Hyde team, able to compete against the top sides in the Premier League but with a bizarre blind spot against lower-ranked teams.

It was a familiar tale at Vicarage Road on Sunday, with United enjoying the lion’s share of possession against Watford but leaving empty-handed after two defensive mistakes in a 2-0 defeat.

United have taken just three points this season from seven matches against Southampton, West Ham, Newcastle, Bournemouth, Aston Villa, Everton and Watford.

But they have beaten Chelsea, Tottenham, Manchester City and held Liverpool to a draw.

Under Ole Gunnar Solskjaer’s management, United have won 73 percent of the Premier League games in which they have had less possession than their opponents, compared to just 36 percent when they have enjoyed more.

But after the Watford match the Norwegian manager, whose team are eighth in the Premier League and seven points off the top four, said the game hinged on a lack of quality, not possession.

“There’s many different reasons for the outcome of a game of football,” he said. “You create chances, you don’t score goals.... It’s got to start with more urgency. We’ve got to play better.”

Man City down but not out

Liverpool may be well on their way to ending a 30-year wait to be crowned champions of England again but Premier League title-holders Manchester City showed their determination to stay in contention with a win over Leicester that ended the Foxes’ 11-match unbeaten run.

Kevin De Bruyne was again in superb form as goals from Riyad Mahrez, Ikay Gundogan and Gabriel Jesus saw City to victory after Leicester striker Jamie Vardy had opened the scoring at the Etihad Stadium.

City, for all they are within a point of Leicester, are still 11 adrift of Liverpool and have also played one more game than the Reds.

But City manager Pep Guardiola insisted: “If we play like we did tonight we can compete with everyone.

“Kevin De Bruyne was incredible tonight – he won the game for us.

“He has always been incredible since we’ve been together. His commitment is incredible. He’s a spectacular player.”