United went down 1-0 – with coach Jose Mourinho fielding a reserve-packed side – on a late goal from Tonny Vilhena, despite a clear offside at the start of the counter-attack.

“Of course I’m unhappy. We lose the game in a moment we didn’t deserve to,” Mourinho said.

“The second half, the game was even. We were always in control. We were trying to win, they were trying not to lose. It is double unlucky because it was a clear offside.

“In the Europa League, we are going to be the team everyone wants to beat.”

Mourinho bemoaned an offside goal, after Tonny Vilhena powered home the winner after 79 minutes, but Nicolai Jorgensen appeared offside as he broke down the wing before crossing to set up the only goal of the game.

United were lacklustre going forward but Mourinho insisted his side did not deserve to lose.

“In that moment we were pushing and they capitalised because it is exactly at that moment where we lose the game,” he said.

“We were double unlucky because it’s a clear offside.”

Mourinho made eight changes from the side which lost the Manchester derby on Saturday, but the Portuguese did not want to discuss individual performances or comment on whether those players given their chance had passed it up in the defeat.

“I don’t want to go in that direction, I don’t want to personalise it,” he said.

“Some of the players were playing their first minutes of the season, there have not been many minutes for them, but obviously some played better than others. I cannot judge them only on one game.”

However, Mourinho said he would revert to a “normal team” for Sunday’s trip to Watford, with the likes of Antonio Valencia and Luke Shaw set to return.

In that same Group A, minnows Zorya were held 1-1 by defiant Fenerbahce, for whom Simon Kjaer scored an injury-time equaliser.

Meanwhile, 2010 European champions Inter Milan surprisingly crashed 2-0 in San Siro against Hapoel Beer Sheva, for whom Miguel Vitor and Maor Bar Buzaglo scored in the second half.

Fellow Italians Fiorentina were held 0-0 at PAOK and Roma could only manage a 1-1 at Viktoria Plzen.

Remarkably, the only Italian side to win were novices Sassuolo – who have never qualified for the European competitions before – with a 3-0 trouncing of 2012 finalists Bilbao on second half goals from Francesco Acerbi, Gregoire Defrel and Matteo Politano.

In that same Group F, Rapid Vienna edged Genk 3-2.

In other early matches, Anderlecht beat Qabala 3-1, Mainz were held 1-1 by Saint-Etienne 1-0 and Zenit battled out a late 4-3 win at Maccabi Tel Aviv.

Astonishingly, Zenit came from 3-0 down to win with four goals in the last 14 minutes – with Luka Djordjevic hitting the winner in injury time.

Also on Thursday, Southampton thumped Sparta Prague 3-0, Ajax won 2-1 at Panathinaikos, Schalke prevailed 1-0 in Nice, Celta Vigo got a 1-1 draw at Standard Liege and Villarreal came from behind to beat Zurich 2-1.

-DPA, PA