Timo Werner ended his goal drought as Chelsea strengthened their grip on fourth place in the Premier League with a 1-0 victory at fellow UEFA Champions League hopefuls West Ham.
Werner had gone 14 games without finding the back of the net for club and country before opening the scoring just before half-time at London Stadium on Saturday.
The Germany forward also missed a golden opportunity in an entertaining derby, which Thomas Tuchel's side deservedly won to go three points clear of the fifth-placed Hammers.
Fabian Balbuena was sent off 10 minutes from time for catching Ben Chilwell after playing the ball as West Ham's hopes of securing a surprise Champions League spot took another blow with five games remaining.
Chelsea made a bright start and Werner flashed a shot over the crossbar after Mason Mount picked him out in the penalty area.
Lukasz Fabianski saved Mount's shot after the lively midfielder turned sharply in the box, and Christian Pulisic fired a first-time strike straight at the West Ham goalkeeper following an excellent run from Werner down the right flank.
Chelsea captain Cesar Azpilicueta breathed a huge sigh of relief when a VAR check ruled he had not handled Tomas Soucek's goal-bound drive in the area and Werner opened the scoring two minutes before the break.
The former RB Leipzig forward was involved in a brilliant sweeping move before racing into the area to finish Ben Chilwell's pinpoint cross with his right foot from seven yards out.
Werner should have doubled Chelsea's lead early in the second half, but he somehow failed to hit the target from a few yards out when following up after Fabianski saved a strike from Mount.
Jesse Lingard went close to equalising with a right-footed attempt that looped just past the far post before Fabianski dived to keep out a long-range drive from the excellent Mount.
The busy Fabianski got down well to deny Werner and the Hammers' hopes of salvaging something from the game took a big blow when Balbuena saw red following a VAR check, having followed through on Chilwell after launching the ball clear.
What does it mean? Blues' fate in their hands
Chelsea look like a side destined to finish in the top four and this was another big step ahead of their Champions League semi-final first leg at Real Madrid on Tuesday.
Sixth-placed Liverpool's draw with Newcastle United earlier in the day was another boost for Chelsea, who have a four-point cushion over last season's champions.
West Ham showed flashes of the quality that has made them unexpected contenders to secure a Champions League spot, but this was another setback following their loss to Newcastle.
Relief for Werner
Werner deserved his long-awaited goal, as he was a constant threat to the Hammers defence with his pace and intelligent runs.
He has now scored 11 goals and assisted nine in all competitions - that combination of 20 involvements being more than any other Chelsea player has achieved.
Werner really should have netted again early in the second half, but that miss did not prove to be costly.
Balbuena dismissal rubs salt in the wounds
Defender Balbuena looked surprised to be given his marching orders by referee Chris Kavanagh, but his contact with Chilwell's leg with his boot looked to be avoidable.
He is the first West Ham player to be sent off in this fixture in the Premier League since Paolo Di Canio in January 2002.
Key Opta facts
- Chelsea have recorded their eighth Premier League double over West Ham, only completing more doubles against Manchester City (10).
- Tuchel is unbeaten in all 10 of his away matches with the Blues (W8 D2) and is only the second manager in Premier League history to remain unbeaten in his first 10 away games in all competitions with a club, after Claudio Ranieri with Leicester City in 2015 (unbeaten in first 11).
- Since Tuchel’s first Premier League game in January, only Manchester City (36) have won more points in the competition than Chelsea (29).
- This was Chelsea’s 10th clean sheet in just their 14th Premier League match under Tuchel, equalling the quickest a manager has recorded 10 clean sheets in Premier League history – Luiz Felipe Scolari also achieved this feat in 14 games back in 2008 with Chelsea. It took Tuchel’s predecessor Frank Lampard three times as many games to reach 10 clean sheets (42 games).
- West Ham have had a player sent off in consecutive Premier League games for the first time since August 2015 under Slaven Bilic, when they went down to 10 men in three games in a row.
- West Ham have lost four of their last eight Premier League matches (W3 D1), as many as in their previous 23 matches in the competition (W13 D6 L4).
Chelsea travel to the Spanish capital for a monumental encounter with last season's Spanish champions, while West Ham are at Burnley a week on Monday.