Goakeeper Ben Foster was denied a stunning stoppage-time equaliser as Chelsea hung on to victory at Watford to move into third in the Premier League.
The former England international raced into the opposition area to get his head on a free-kick and forced a brilliant save from Kepa Arrizabalaga.
The visitors had earlier only had to wait five minutes to open the scoring as Jorginho whipped a delicious ball into the area for Tammy Abraham to lift in for his 10th goal of the season.
Foster made two superb stops to prevent Frank Lampard’s side going further ahead before the break as he denied both Christian Pulisic and Mason Mount.
But he could not prevent Pulisic following up his hat-trick against Burnley last Saturday with another goal as the American tucked in Abraham’s low cross.
Watford, who remain bottom of the Premier League and are still searching for their first league win of the season, were handed a lifeline when Gerard Deulofeu tucked in a video assistant referee-awarded penalty, his first goal of the season.
Foster almost snatched a point for Watford in the last passage of play but Chelsea survived for a fifth successive away win in the league, and a club-record equalling seventh away victory in all competitions.
Lampard’s side can slip back into fourth behind Leicester, who face Crystal Palace on Sunday and have a superior goal difference, yet it was another impressive step forward for his young side who are now two points behind second-placed Manchester City.
Chelsea show style and substance in gritty win
Chelsea’s defeat by Manchester United in the Carabao Cup ended their seven-game winning run, but on the evidence of this game it has done little to dent their confidence.
With Abraham, Mount and Willian restored to the team, and Jorginho and Mateo Kovacic pulling the strings in midfield, Watford struggled to get hold of the ball in the early stages.
When the hosts finally had a sustained period of possession after half an hour, they could have been three goals down.
Abraham’s opener was a work of wonder from Jorginho, who is now a fans’ favourite after becoming a lightning rod for the frustration last season under Maurizio Sarri.
But Chelsea’s top scorer could have had a second as Foster also stopped Pulisic’s header and somehow tipped Mount’s shot onto the bar, also denying the midfielder again in the second half after a fast break.
Although Chelsea finished third last season, their away form often faltered under Sarri. This season, however, they are showing steel, suggesting that a similar finish may be possible despite losing Eden Hazard in the summer and being in the midst of a two-window transfer ban.
Win eludes Watford again despite soft penalty
Watford boss Quique Sanchez Flores said in his programme notes that he can “feel” his team getting closer to their first Premier League win of the season following three successive draws.
Setting up in 5-3-2 system, they had to contain Chelsea for the first half hour, as the visitors threatened to put the game out of sight.
But following Foster’s heroics, they grew into the game as half-time approached, giving their shivering fans something to warm to.
Deulofeu’s fizzing effort was the closest they came before the break and Kurt Zouma had to be sharp to block Andre Gray’s early second half shot.
Once Pulisic scored his fourth of the season, the game looked to have petered out and yet there was still time for VAR to intervene with 10 minutes remaining.
Having been on the wrong end of two VAR decisions against Tottenham last month, Watford will not have minded that the penalty award looked soft.
Jorginho appeared to trip Deulofeu but the contact looked minimal, with referee Anthony Taylor deciding against the spot-kick.
The VAR thought differently, and although Watford pressed for an equaliser with Arrizabalaga saving from Foster’s header in injury time, Chelsea fans were able serenade “Super Frankie Lampard” once again on the road.