Chelsea exuded a title-winning mentality to overcome a spirited Watford performance and take all three points on the road.
The Hornets were up for the occasion and Mason Mount’s opener came against the run of play. It was no surprise to see them draw level when Emmanuel Dennis scored before half-time. A quality attacking move brought about a second for the Blues as they escaped a scare.
Claudio Ranieri made just one change to face his former side. Joao Pedro came back into the attack.
Thomas Tuchel suffered a pre-match blow as in-form man Reece James failed a late fitness test. With Ben Chilwell also injured, Marcos Alonso and Cesar Azpilicueta filled in on the flanks.
Andreas Christensen returned to the side in place of Thiago Silva, while Jorginho was ruled out too. Saul Niguez took his spot in the centre of the park.
A whole different front three to the weekend draw with Manchester United was deployed. It saw Mason Mount, Christian Pulisic and Kai Havertz enter the starting XI.
Watford nearly stunned the league leaders early on. Tom Cleverly pressured and then beat Alonso to the ball, before pulling back for Pedro, whose shot was cleared off the line.
The hosts then went close again when Kiko Femenia’s cross deflected off Azpilicueta. Edouard Mendy had to pull off an acrobatic save to prevent the own goal.
Watford maintained their pressure on a sloppy Chelsea side in the first 10 minutes, before play was stopped.
Adam Masina was forced off and replaced by Danny Rose. And then a medical emergency in the crowd became the priority at Vicarage Road, with the players exiting the pitch.
The match resumed after a lengthy stoppage and the visitors nearly scored with their first attack of the game.
The ball bounced to Mount in the box and the England international struck the post with a volley from a tight angle.
Mount finds the opener
He did find the target just before the half hour mark, though. Alonso brought down a chipped through ball expertly and passed to Havertz, who set up Mount to find the bottom corner.
It could have been two-nil soon after had Pulisic played his pass quicker. After running forward he waited too long to feed Havertz, who converted but saw the offside flag raised.
Watford returned on the offensive and continued to unease their opponents. They caused a scare when the ball broke to Rose and his low strike pulled Mendy into action once more.
And then they struck back through Dennis. The forward progressed into the box and placed the ball into the bottom left corner.
They weren’t content with stopping there before half-time. Dennis, who was causing massive issues down the right, fed Moussa Sissoko who should’ve scored but scuffed his effort after beating the offside trap.
Tuchel made a change at the break after seeing his side be overrun in the opening 45. Saul was taken off again in the Premier League, and Silva came on.
Chelsea started the second half better than they had the first. Havertz strode forward and found Pulisic, but Watford got back well and cut out the threat.
Tuchel changes pay dividends
Both Mendy and Trevoh Chalobah then suffered knocks. The latter couldn’t continue with his hamstring issue, so was replaced by Hakim Ziyech.
The attacker had barely been on the pitch five minutes when he was booked for a cynical foul as he cut out a counter-attack.
Romelu Lukaku was introduced for Azpilicueta in the Blues’ third and final substitution.
The attacking intent from Tuchel had an instant impact with Mount crossing low for Ziyech to fire into the roof of the net and restore the lead.
Ziyech nearly added a second to his tally when Havertz picked him out with a cross. Daniel Bachmann got down low to stop his headed effort.
Bachmann had to be on alert again when the ball was fed from Lukaku to Havertz to Pulisic. He claimed the eventual cross into the box.
Then Mendy was forced into making a stop. Substitute Juraj Kucka stung his palms with a long-range free-kick, before the full-time whistle was blown.