United slumped to a 2-0 defeat to Olympiakos in the last 16 of the Champions League after Dominguez and Campbell scored in each half of the first leg match. (Getty Images)
Greece: Manchester United's terrible season got even worse Tuesday night when the English power lost 2-0 at Olympiakos in their second-round Champions League opener.
Alejandro Dominguez deflected Yiannis Maniatis's shot past David de Gea in the 38th minute, and Joel Campbell caught the goalkeeper off guard with a well-placed strike in the 55th minute at Karaiskaki Stadium.
United are just sixth in the Premier League at 13-8-6 and trail Liverpool by 11 points for fourth place, the final berth in next season's lucrative Champions League. Winning this year's competition might be the only route into next year's tournament for United, who would face a major revenue loss if they fail to qualify for Europe's top club tournament.
The second leg of the total-goals series is in Manchester on March 19.
United had the 55 percent possession but were outshot 12-5. Wayne Rooney failed to threaten and Robin van Persie missed his team's best chance, skying a shot over the crossbar following Chris Smalling's cross in the 82nd minute. Olimpiakos became the first home team to win in six second-round matches.
In the night's other game, Robert Lewandowski scored twice and led Borussia Dortmund to a 4-2 victory at Zenit St. Petersburg.
Dortmund, who lost to Bayern Munich in last year's final, took a 2-0 lead when Henrikh Mkhitaryan scored in the fourth minute and Marco Reus added a goal 70 seconds later.
Zenit, playing their first competitive game since Dec. 11, cut the gap on Oleg Shatov's goal in the 57th, but Lewandowski made it 3-1 four minutes later. Hulk converted a penalty kick for Zenit in the 69th and Lukasz Piszczek scored Dortmund's final goal two minutes later.