Diego Costa's late goal earned Antonio Conte's Chelsea a 2-1 win over West Ham at Stamford Bridge on Monday.
The Blues were largely dominant and took the lead shortly after half-time through Eden Hazard's penalty.
The introduction of Dimitri Payet looked to have helped the Hammers, who lost record signing Andre Ayew to injury in the first half, snatch a point as his corner was turned in by James Collins in the 77th minute.
However, Costa finished from outside the box in the 89th minute to give the hosts a victory that, on the balance of play, was deserved.
While West Ham handed competitive debuts to three players - Arthur Masuaku, Ayew and Havard Nordtveit - the hosts had 10 players in their XI who started the opening game last season.
The only one to miss out in Conte's first competitive match in charge was Cesc Fabregas, who made way for summer signing N'Golo Kante.
The former Leicester midfielder did not take long to make his mark, receiving a yellow card after less than three minutes for bringing down Andy Carroll.
But, after a tentative opening 10 minutes, Chelsea settled into the game and started to dominate possession.
Branislav Ivanovic forced Adrian into a sharp low save at his near post before Oscar was denied a penalty when he went down under a challenge from Winston Reid, who stuck out an arm as the Brazilian knocked the ball past him into the box.
Hazard, who enjoyed a bright first half, then shot narrowly wide after driving down the left flank.
West Ham lost record signing Ayew to injury after 35 minutes, with another summer addition, Gokhan Tore, coming on in his place.
Chelsea continued to control the game as Costa shot over and Willian saw a free-kick saved before the end of the half.
The hosts got the breakthrough shortly after the restart as Michail Antonio fouled Cesar Azpilicueta in the box and Hazard fired the penalty into the roof of the net.
Antonio was replaced by Sam Byram a few minutes later but chances continued to come for Chelsea.
Adrian saved from Willian before John Terry headed over the bar from a corner.
Slaven Bilic opted to introduce Payet after 67 minutes and it was from his corner that Collins fired home the equaliser.
Chelsea, though, still pressed and, after Pedro volleyed wide, Costa drilled home the winner from just outside the box.
Payet spurned a chance to equalise with a first-time shot that was held by Thibaut Courtois and Chelsea held out for victory.
Player ratings
Chelsea: Courtois (6), Ivanovic (7), Cahill (7), Terry (7), Azpilicueta (6), Kante (6), Matic (6), Willian (7), Oscar (7), Hazard (8), Costa (7).
Subs: Pedro (5), Moses (5), Batshuayi (5).
West Ham: Adrian (6), Antonio (5), Reid (5), Collins (6), Masuaku (5), Kouyate (5), Nordtveit (5), Noble (5), Ayew (5), Carroll (4), Valencia (4).
Subs: Tore (5), Byram (5), Payet (6).
Man of the match: Eden Hazard.
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