Shakhtar Donetsk handed Chelsea their first Champions League defeat since winning the trophy last season with a 2-1 victory at the Donbass Arena.
Alex Teixeira's goal in the opening minutes came against the initial run of play, but by the time Fernandinho doubled the Ukrainian champions' lead early in the second half, Shakhtar were comfortably the better of the two sides.
The hosts could have had an even bigger advantage heading into the closing stages courtesy of their Brazilian contingent of players, including longtime Blues target Willian, but for some strong stops from Petr Cech.
And it was another Brazil star in Oscar who forced a tense finale with a consolation goal two minutes from time, but the defending champions reach the halfway point of Group E with just four points following a win, a draw and a defeat.
Shakhtar has never lost at home to an English club, winning three matches and drawing one.
"We're playing better, and better, this is probably the best game Shakhtar has played,'' Shakhtar coach Mircea Lucescu said. "We played spectacular football. The score easily could have been 4-1 in our favor.
"Now it's time to think about the return match in London. Chelsea opened the match too relaxed, but when they started to press and tried to score, it was too late, we were already in control of the match.''
The two teams will next play in London in two weeks' time, while Nordsjaelland host Juventus on the same day.
Donetsk now lead Group E with seven points from their first three games, three clear of second-placed Chelsea after Nordsjaelland secured their first-ever Champions League point at home to Serie A winners Juventus.
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Manchester United 3-2 Sporting Braga
Javier Hernandez grabbed a brace as Manchester United came back from 2-0 down to beat Braga in their Champions League clash at Old Trafford.
Braga took a surprise lead at Old Trafford after just 90 seconds as former Newcastle United man Hugo Viana picked out Alan with a fantastic cross and the forward made no mistake as he headed the ball past David de Gea in the United goal.
Alan grabbed his and Braga's second of the night on 20 minutes as Eder skipped past Michael Carrick and found Alan with a low cross. The Braga striker hit a well placed, first-time shot beyond De Gea and the Portuguese side appeared on course for a famous win.
United's Mexico striker Hernandez quickly replied from Shinji Kagawa's cross, Jonny Evans equalised from close range in the 62nd minute and Hernandez headed the winner 15 minutes from time.
Hernandez has become a bit-part player for United with the arrival of Dutch striker Robin van Persie, but took his chance to impress on only his fourth start in all competitions this season.
United, who have lost only one of their last 37 Champions League home games, have nine points from three matches and are poised to reach the last 16. CFR Cluj are on four after a 1-1 draw at Galatasaray, Braga have three and the Turkish side are bottom with one.
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