Tottenham went top on goal difference from Liverpool on 21 points after a 0-0 draw with third-placed Chelsea, who are two adrift with 19.

Timo Werner thought he had scored the opener for Chelsea in 11 minutes but it was disallowed for offside, while Serge Aurier came closest to scoring for Spurs when goalkeeper Edouard Mendy parried his long distance effort.

Mason Mount was denied a winner for Chelsea in the 80th-minute after Tottenham's Hugo Lloris made a stunning save.

Southampton defender Jan Bednarek headed in a corner at the near post and James Ward-Prowse curled a free-kick beyond United goalkeeper David de Gea, who was substituted with a knee injury at half-time.

Cavani was brought on at the start of the second-half and made an instant impact by setting up Bruno Fernandes' 59th-minute strike before heading in an equaliser on 74 minutes and racing through to score an injury-time winner.

"At the end I was so proud at 2-2 because we did so well," said Solskjaer.

"It is a trait of Manchester United to never give in. Every single one of them, there was absolutely no chance they were going to give up."

The win lifts Manchester United to seventh with 16 points, one behind fifth-placed Southampton.

Even though United made the more confident start against Southampton, they fell behind when Bednarek flicked an awkward, in-swinging corner from his captain Ward-Prowse.

Ward-Prowse then proved why he is a free-kick specialist as he caught de Gea out with an inch-perfect effort that put the Spanish goalkeeper out of the game as he smashed his knee into the post reaching for the ball.

Dean Henderson was swapped for De Gea after the half-time break as a precaution and with a Champions League tie on Wednesday.

For a 33-year-old, Cavani had a youthful determination to change the game in the second-half.

Cavani's first approach was to set up an unmarked Fernandes for a sweeping finish before the Uruguayan striker poked in a header from Fernandes' deflected strike.

He accomplished the turnaround mission with three of five minutes injury time left as Cavani swooped in behind Southampton's lines for another poacher's goal from close range to clinch three points in dramatic fashion.

Wolves meanwhile moved into the top six with a 2-1 away win over Arsenal, who dropped to 14th in the standings.

Pedro Neto opened the scoring for Wolves in the 27th minute before Gabriel equalised three minutes later.

Daniel Podence then grabbed the winner for Wolves in the 42nd minute.

The match was marred by the head injury sustained by Wolves forward Raul Jimenez, who clashed heads with Arsenal defender David Luiz while jumping for the ball.

Jimenez lay motionless on the field before being stretchered off and taken to hospital where he was making good progress.

Australian Associated Press