Olympiakos shock Man United

Manchester United suffered a 2-0 defeat to Olympiakos in the Champions League.

Manchester Unites' Michael Carrick, heads the ball away during the Champions League last 16 firast leg against Olympiakos Piraeus in Athens on 25 February 2014. Picture: Facebook.

ATHENS - Manchester United's dwindling hopes of lifting a trophy this season are dangling by a thread after they produced an abject display to lose 2-0 at Olympiakos Piraeus in a Champions League last-16 first leg on Tuesday.

Alejandro Dominguez opened the scoring with a clever first-half flick and Arsenal loanee Joel Campbell added a sublime second goal to leave United facing a huge task to overturn the deficit in the return match at Old Trafford on 19 March.

"That's the worst we've played in Europe. We didn't deserve to get anything," manager David Moyes told reporters. "I'm surprised, I didn't see that level of performance coming.

"I take responsibility, we have to play better. The players are hurting."

Defeat at the Georgios Karaiskakis Stadium represented yet another body blow in an inauspicious campaign for last season's English Premier League title winners.

United are out of the FA Cup and the League Cup and trail Premier League leaders Chelsea by 15 points with 11 games left to play.

Moyes's men looked sluggish and disjointed against an inexperienced Olympiakos side who are bidding to reach the quarter-finals for only the second time in their history.

It was the first time the Greeks had beaten United in five attempts.

"To beat a great side like United, the way we did, is something very special and I can't hide the joy and pride I feel for my players," said Olympiakos coach Michel.

"We picked the best moment to show Greek football is alive and kicking," added the former Spain and Real Madrid striker.

Moyes opted to start with two wingers, Antonio Valencia and Ashley Young, but neither made an impact in a first half in which runaway the Greek league leaders displayed real energy and hunger.

Strike pair Wayne Rooney and Robin van Persie were peripheral figures for the visitors as pot shots on goal from Giannis Maniatis and Hernan Perez lifted the home supporters.

In other results, Borussia Dortmund's Robert Lewandowski scored twice in a clinical 4-2 win at Zenit St Petersburg who were made to pay for some dreadful defending in their Champions League last 16, first-leg tie on Tuesday.

Dortmund grabbed two goals in the first five minutes through Marco Reus and Henrikh Mkhitaryan after Zenit, looking rusty as they started their first match after a two-month winter break, twice lost possession on the halfway line.