Paris - A miserable season for Louis van Gaal and Manchester United took a new turn for the worse on Thursday as they lost 2-1 away to Danish champions Midtjylland in the Europa League.
Goals from the talented Pione Sisto and young Nigerian forward Paul Onuachu gave Midtjylland the victory in Herning after Memphis Depay had put a weakened United side ahead in the first leg of their last-32 tie.
That away goal gives United every chance of turning things around in next Thursday's return at Old Trafford but the spectre of a humiliating exit hangs in the air at a time when Van Gaal's side lag behind in their bid to finish in the top four of the Premier League.
The Dutch manager has admitted winning the Europa League may now be his side's best chance of qualifying for next season's Champions League and this latest setback will only increase the pressure on Van Gaal.
He sent out a weakened side with Sergio Romero starting in goal, and the likes of Paddy McNair and Donald Love featuring from the start against opponents who eliminated Southampton earlier in the competition.
Depay has been a disappointment since his big-money arrival from PSV Eindhoven but he put the visitors in front in the 37th minute, bundling the ball in at the second attempt following a Jesse Lingard cross.
However, Midtjylland were back level a minute before the interval thanks to Sisto as the Ugandan-born Danish international smashed a shot past Romero in the United goal.
Midtjylland were playing their first competitive game in more than two months due to the long Danish winter break but they appeared to want the win more and they got it thanks to Onuachu, whose low shot from just outside the area sneaked past Romero.
"It's just not good enough. It's not acceptable. It's got to be a lot better," admitted United midfielder Michael Carrick, speaking to BT Sport.
"We didn't really kick on after we scored. With a performance and a result like that we go home very disappointed."
United face League One Shrewsbury Town in the FA Cup next Monday before the return against Midtjylland next Thursday.
Premier League title contenders Tottenham Hotspur, meanwhile, came away from their trip to Italy to face Fiorentina with an excellent 1-1 draw that puts them in a strong position ahead of next week's return.
Mauricio Pochettino sent out a strong side, albeit one missing first-choice goalkeeper Hugo Lloris and with Harry Kane on the bench.
And Spurs went in front in the 37th minute when Nacer Chadli converted from the penalty spot after Ben Davies was brought down by Nenad Tomovic.
However, Fiorentina, who sit third in Serie A, drew level just before the hour mark thanks to Federico Bernardeschi, whose long-range strike beat Michel Vorm with the aid of a deflection off Ryan Mason.
In a strong Europa League line-up, Borussia Dortmund put themselves in a strong position against FC Porto as they beat the Portuguese giants 2-0 at the Signal Iduna Park thanks to a goal in each half from Lukasz Piszczek and Marco Reus.
Holders Sevilla have one foot in the last 16 after beating Molde of Norway 3-0 at the Sanchez Pizjuan with Fernando Llorente netting twice before Kevin Gameiro wrapped up the win.
Fellow Spaniards Villarreal beat Serie A visitors Napoli 1-0 via a late goal from Denis Suarez, while Anderlecht beat Olympiakos by the same score as Serigne Mbodji got the only goal of the game in Brussels.
Basel, whose St-Jakob Park will host this season's final, remain in contention after losing 3-2 to Saint-Etienne in France.
Jean-Christophe Bahebeck, on loan from Paris Saint-Germain, got the winner for the French side after Basel had earlier come from two goals down.
Moustapha Sall and Kevin Monnet-Paquet scored to put Saint-Etienne 2-0 up before veteran Argentine defender Walter Samuel pulled one back and Marc Janko equalised with a penalty.
Later games include Liverpool taking on Bundesliga side Augsburg as Jurgen Klopp goes back to his native Germany for the first time since becoming Reds manager earlier this season.