Wayne Rooney's late long-range strike was not enough to salvage a draw for Manchester United as they lost 2-1 to Fenerbahce in the Europa League.
Moussa Sow's second-minute overhead kick and a second-half Jeremain Lens free kick had put the Turkish side in a commanding position as Paul Pogba limped off injured.
Rooney's strike saw him equal Ruud van Nistelrooy's record as United's all-time European top scorer, but it was too late to spur a comeback.
Fenerbahce's players, helping by the baying Sukru Saracoglu Stadium crowd, continued to make life uncomfortable for United, who lost world-record signing Pogba after 30 minutes following a heavy challenge from Josef de Souza.
Zlatan Ibrahimovic was fortunate that his altercation with Simon Kjaer was missed by officials as tempers frayed, with Jeremain Lens, on loan from Sunderland, adding to United's problems with a superb second-half free kick.
Rooney's 89th-minute drive led to a frantic ending, but Fenerbahce held out to secure a memorable victory that sees them usurp United in the Group A qualification spots.
United, who are winless in their last nine European away games having lost eight of them, made three changes with Rooney, Anthony Martial and Morgan Schneiderlin coming into the side in place of Zlatan Ibrahimovic, Juan Mata and Jesse Lingard.
The intimidation aspect played a part from the outset. A cacophony of noise greeted United at the warm-up and it only increased as kick-off approached, with the emotions peaking within 65 seconds.
Hasan Ali Kaldirim floated in a cross from the left and could not have foreseen Sow meeting it with such an exceptional overhead kick, beating David De Gea to send the Fenerbahce support wild.
It was a sucker punch similar to that dealt at Stamford Bridge recently when Chelsea dished out a 4-0 shellacking, so United were relieved to see Souza miss the target with a header after being left unmarked from a free-kick soon after.
Schneiderlin was booked for the clumsy challenge that led to that free-kick and Ander Herrera soon joined him in the referee's notebook, just days after being sent off for two against Burnley.
Mourinho's side were looking shaky without the ball and struggling to create chances when they had it, with Marcus Rashford's wayward strike across goal the best they could muster in the opening 20 minutes.
Rooney would have been through had a heavy touch not seen a clever Anthony Martial ball go to waste before Pogba left the field with what looked like a dead leg.
The France international limped heavily after a heavy challenge and trudged off after 30 minutes, with Lens wasting a counter-attack before Ibrahimovic could be brought on.
His introduction brought a spell in the ascendancy and only goalkeeper Volkan Demirel's intervention prevented Rashford's low cross being turned home by the veteran striker.
Ibrahimovic also brought an added spice to the match, grabbing Kjaer by the neck leading to him being booed by the home supporters throughout the game.
Rooney also irked the home faithful having been infuriated by the way Souza threw himself to the deck, leading the teams to clash as the fans were further antagonised.
Mata replaced Schneiderlin ahead of the second-half meaning, as well as the Spaniard, United had the attacking talents of Rooney, Rashford, Martial and Ibrahimovic on the pitch but it failed to spark them into life.
Rooney, playing in a deeper position, glanced a header just wide of the right-hand post, which Mata just evaded with a snap shot.
Fenerbahce, though, were playing smartly and winning free kicks whenever they could.
United could not believe referee Milorad Mazic ruled that Ibrahimovic had fouled Mehmet Topal and were even more shocked to see Lens superbly bend home the resulting free kick.
It was an exceptional goal that substitute Emmanuel Emenike could have added to following his 68th-minute introduction. The former West Ham loanee could not beat De Gea having been unsteadied by Daley Blind, before forcing the Spaniard into a save from distance and then just missing a low cross.
The match looked to be petering out until Rooney rolled back the years, rifling home a stunning strike from distance. It led to a frantic ending as a timely block was followed by one that United felt should have led to a penalty, with handball appeals against Martin Skrtel from Herrera's shot.