Burnley shocked nine-man Chelsea by beating the champions 3-2 in a thrilling opening Premier League encounter at Stamford Bridge.
Captain Gary Cahill was shown a straight red card early on by Craig Pawson for a high tackle on Steven Defour, before Sam Vokes put Burnley ahead (24) with a neat flick inside the area.
Stephen Ward doubled Burnley's lead with a fierce strike from an angle (39), and Vokes netted again before the break (43) with a free header six yards out.
Substitute Alvaro Morata pulled one back for Chelsea on his debut (69), but Cesc Fabregas was shown a second yellow for a foul late on, having earlier been booked for a sarcastic clap towards Pawson.
For Chelsea, Jeremie Boga started behind Michy Batshuayi for his debut as new signing Alvaro Morata made the bench, but Boga was subbed off after 18 minutes following Gary Cahill’s red. Antonio Rudiger made his debut for the Blues following his summer move from Roma.
For Burnley, new signing Jon Walters was on the bench, as Sam Vokes started up front.
David Luiz's late goal (88) made for a nervy ending, but Burnley held on for a dramatic victory.
Chelsea were reduced to 10 men after just 14 minutes as Cahill overran the ball in midfield, before going in studs up on Defour, forcing Pawson to show a straight red.
There were no complaints from new skipper Cahill, but disgruntled Chelsea fans made their feelings known to Pawson before Burnley took the lead on 24 minutes through Vokes, flicking Matt Lowton's right-wing cross into the bottom far corner from 12 yards.
Chelsea: Courtois (5), Rudiger (4), Luiz (4), Cahill (3), Azpilicueta (5), Kante (5), Fabregas (4), Alonso (5), Boga (4), Willian (5), Batshuayi (5)
Subs: Christensen (5), Morata (6), Musonda (NA)
Burnley: Heaton (7), Lowton (7), Tarkowski (9), Mee (7), Ward (8), Gudmundsson (7), Cork (8), Hendrick (7), Defour (8), Brady (8), Vokes (9)
Subs: Arfield (6), Walters (6)
Man of the match: Sam Vokes
Ward made it 2-0 with a thunderous left-footed effort from an angle after Jack Cork's deft ball into his path, and Vokes then got his second, and Burnley's third, with two minutes of the half remaining, ghosting between Luiz and Marcos Alonso to head home Defour's cross.
Chelsea pushed in the second half as Alonso forced two good saves from Tom Heaton, and Morata, who had been introduced just 10 minutes earlier, headed home from close range after Willian's fine cross for 3-1.
Morata then netted at the far post, but was correctly flagged offside, before Fabregas received a second yellow for a silly late foul on Cork.
Nine-man Chelsea continued to push, however, and somehow halved the deficit as Luiz volleyed home Morata's flick-on inside the area.
Robbie Brady hit the post from a free-kick a minute later, but after a frantic final few minutes inside Burnley's penalty area, Sean Dyche's side were delighted to hear the final whistle.
- Chelsea are only the second reigning Premier League champions to lose the opening game of the following campaign (also Leicester last season).
- Chelsea are the first reigning Premier League champions to concede three goals in the opening game of the next season.
- Chelsea are the first side to pick up two red cards on the opening day of a Premier League season.
- Sam Vokes has netted seven goals in his last six Premier League games, after managing just five in his previous 58.
- This is the first time that the reigning champions have suffered a defeat on the first matchday in successive top-flight seasons since 1968 (Man Utd 1967/68 & Man City 1968/69).
The pundit - Paul Merson
You look at City's bench compared to Chelsea's and it is chalk and cheese. This is not a bad team overnight and next week they go to Spurs.
As a Burnley player and you see their bench before kick-off and there is only Morata on it. The next couple of weeks is massive for Chelsea Football Club and you cannot afford to drop points at home to Burnley.
Antonio Conte: The Cahill sending off was a key moment, because to play the rest of the game with 10 men, and then with nine men, is not easy. But in the last three games we end the game with 10 men or less.
I think I will have to adapt a new system to play with nine men or 10 men for the next game, to anticipate this situation!
Sean Dyche: I thought the referee was fantastic, to handle the occasion, the stadium, the decisions, my staff tell me he's got them right. It's a good day for my players and the fans today.
The win quietens down a few stories, the first win is important, especially when we're written off like we are every year. It kills a few things off early doors, and allows the players just that little edge of growth.
Man of the match - Sam Vokes
It was a close battle between the Welshman and his team-mate James Tarkowski, but Vokes' two goals showed what a danger he can be inside the box.
His first, a flick as the ball came in slightly behind him, showed great improvisation, and though his second was bread and butter for any striker, his all-round work rate was superb.
He won 12 aerial duels as David Luiz and Antonio Rudiger were treated to a rough afternoon, and also won three fouls for Burnley having held the ball up well.
Champions Chelsea go to Wembley to face Tottenham on Sunday, live on Sky Sports Premier League, while Burnley host West Brom on Saturday at 3pm.