Manchester United's troubled season took another turn for the worse this morning as David Moyes' side slumped to a 2-0 first leg defeat to Olympiakos in the last 16 of the Champions League.

Argentine striker Alejandro Dominguez broke the deadlock at Karaiskaki Stadium when he got his foot to a shot from Yiannis Maniatis in the 38th minute and turned the ball past goalkeeper David de Gea.

First-half composure from the visitors soon turned to complacency after the break when striker Joel Campbell, on loan from United's Premier League rival Arsenal, caught De Gea off guard with a well-placed shot in the 55th minute.

Wayne Rooney produced no threat up front and strike partner Robin van Persie missed the visitors' only clear chance a shot over the crossbar in the 82nd minute as United slipped to its first defeat in the Champions League this season.


"This was a great victory against a massive club like Manchester. We were told to hold the midfield and we did,'' Maniatis said.

"The fans were amazing and we made them happy. It's fantastic.''

Runaway leaders in the Greek league, Olympiakos fielded its untested strikers after the sale last month of Kostas Mitroglou. But the hosts threatened early with Dominguez nearly grabbing a goal in the eighth minute, stopped only by a last-ditch tackle from Nemanja Vidic.

Despite the defeat, United midfielder Michael Carrick insisted that the three-time European champions could turn the result around in the second leg on March 19 at Old Trafford.

"We just haven't been getting the right results,'' Carrick said. "As players we have to stand up ... that's the business we're in.''

Premier League champions last season under Alex Ferguson, United is currently sixth in the domestic standings 15 points adrift of leader Chelsea. It also made an early exit from the FA Cup at the hands of Swansea.