Watch: Clutch Diego Costa goal gives Chelsea win over West Ham
Chelsea gave Antonio Conte a win in his official managerial debut, with Diego Costa's 89th-minute strike the difference in a 2-1 win over West Ham at Stamford Bridge on Monday.
Chelsea, which endured the worst title defense of all time in settling for a 10th-place finish last season, also got a goal from Eden Hazard, while N'Golo Kante made his club debut after helping Leicester City dethrone the Blues last season.
West Ham, meanwhile, entered the season with heightened expectations after last season's seventh-place finish (and just four points out of a Champions League spot). but midfield maestro Dimitri Payet began the campaign on the bench as he works his way back from a summer that included a Euro 2016 run to the final with France. The club's record signing, Andre Ayew, earned the start, but he exited with an injury, limping off after 34 minutes.
Willian nearly gave the Blues the lead on the stroke of halftime, but his long-range free kick was expertly tipped over the bar by West Ham goalkeeper Adrian.
Chelsea finally opened the scoring in the 47th minute through Hazard, who rifled home a penalty kick. Cesar Azpilicueta was fouled by Michail Antonio a minute into the second half, and Hazard made no mistake with his powerful attempt.
After shockingly waiting until April to score his first league goal last season, the goal in the season debut is surely a welcome sight for Hazard and Chelsea fans.
James Collins stunned the Stamford Bridge faithful in the 77th minute with an equalizer seemingly out of nowhere. Seconds after appealing for a Chelsea handball, which was not granted, Collins had a ball in the box squirt his way, and he uncorked a left-footed blast that found its way through traffic and by Thibaut Courtois to make it 1-1.
When it appeared to two sides were headed to a draw, Costa restored Chelsea's lead in the 89th minute. Michy Batshuayi, just into the game for his Chelsea debut, knocked the ball down for Costa, who settled and let a low shot fly from about 23 yards out. He found the lower left-hand corner to beat Adrian, giving Chelsea a 2-1 edge and sparking celebrations from Conte on the sideline.
Chelsea faces a short turnaround, as it travels to face Watford on Saturday.
West Ham has an even shorter turnaround, as it will aim to bounce back in the Europa League playoff round on Thursday with its first leg match against Romania's Astra. The Hammers return to league play Sunday against Bournemouth.