Fenerbahce scored two stunning goals to beat Manchester United and leave Jose Mourinho’s side in danger of Europa League elimination.
Striker Moussa Sow gave Fenerbahce the lead within 65 seconds with an overhead kick which sailed over David de Gea, and Jeremain Lens curled in a brilliant free-kick in the second half.
The visitors dominated possession but saw world-record signing Paul Pogba go off with a leg injury in the first half.
Captain Wayne Rooney smashed in a 25-yard consolation goal late on.
Defeat means United are third in Group A – one point behind leaders Feyenoord and Fenerbahce – with two games left, against the Dutch side at Old Trafford and away to Ukraine’s Zorya Luhansk.
Qualification for the next stage remains in the Reds’ hands, but they will need to be more incisive against their next opponents.
Sow about this then?
The Turkish side went ahead in spectacular fashion with the first attack of the game…
And it got better in the second half…
Too little, too late
Despite having 70% possession in front of an intimidating Istanbul crowd, United rarely tested goalkeeper Volkan. Their play was often slow and ponderous, allowing the opposition to retain their defensive shape.
They only really threatened once Rooney had converted his superb goal in the 89th minute.
The England skipper went close with a header in injury time while Ander Herrera had a goalbound strike blocked by Martin Skrtel.
Since putting four past the Turks in Manchester two weeks ago, the Red Devils have found the net just twice in their last four games.
Restored to the starting line-up on Thursday, Rooney has two goals in 14 games this season, while Zlatan Ibrahimovic, who came off the bench to replace the injured Pogba, has scored once in his last 11 matches.
Mourinho also sent on out-of-favour midfielder Henrikh Mkhitaryan for his first appearance since 10 September, but the Armenian failed to make an impact.
These two sides were once Champions League regulars and met at the group stages in 1996 and 2004, but have tumbled into the second tier of European competition this season.
Both may have to be content with the same next term following their struggles in the league, with 19-time champions Fenerbahce fifth in Turkey, while 20-time winners United are languishing in eighth in England.
Boss Mourinho was given a one-match touchline ban and £58,000 fine on Wednesday for an incident at half-time during the Premier League draw against Burnley and commenting on the referee before the match against Liverpool.
And a bad week got worse following defeat against Dick Advocaat’s side.
The Portuguese had said in July 2013 – when returning as Chelsea boss for a second time – that the club did not have a successful 2012-13 season despite winning the Europa League under Rafael Benitez, but changed his opinion prior to this match stating is has “new meaning for big teams” as the winners can qualify for the Champions League.
Yet the loss leaves them with the prospect of falling at the first hurdle in the competition.