Lucho Gonzalez scored early in the second half to steer Marseille to a 1-0 victory over Olympiakos in their opening Group F game of the Champions League on Tuesday.

The Argentine midfielder exploited a lapse in the Greek side's defense and met a cross from Jeremy Morel to score in the 51st minute, beating his former River Plate teammate Franco Costanzo in the Olympiakos goal.

Earlier, 10 Marseille fans were arrested in central Athens after briefly clashing with police. Riot police had been deployed in the city for a demonstration held by striking taxi drivers.

The French team dominated most of the game at Karaiskaki Stadium, but created few scoring opportunities. Putting aside a dismal start in the French league, Tuesday's game gave Marseille an early lead in the group after Dortmund drew 1-1 at home to Arsenal.

"Of course it's great to win a game at this top level of competition. It's a result that will give us calm and confidence,'' Marseille coach Didier Deschamps said.

"What was key for us was that we really wanted the win and went for it. Olympiakos is a big club with great fans - we didn't beat a small team tonight - but we handled the pressure well.''

Marseille defender Rod Fanni was sent off in injury time for a reckless tackle on Kevin Mirallas.

"The end of the match was difficult,'' Deschamps said. "They could have leveled, and we were giving the ball away too easily. So that's the one thing I wasn't happy about.''

Loic Remy missed a chance for the visitors in the 37th minute when his shot his the bar, while Rafik Djebbour could have snatched a draw for the Greek champion in the 75th but sent the ball high after a cross from Vassilis Torosidis.

Olympiakos squandered a strong start, with Mirallas missing three first-half chances.

The Greek side have had an unconventional start to the season, missing two matches in the domestic league after teams were relegated over a match-fixing scandal that left gaps in the fixture list.

Coach Ernesto Valverde brought on Djebbour and Jean Makoun for the home side in the second half to try and shake up the attack, but Marseille retained control, helped by standout midfielder Benoit Cheyrou.

"It's true that we didn't create enough chances. European and domestic competitions are very different,'' Valverde said. "There are a lot of new players in the squad and some of them are not well integrated yet.

"So in the next matches, we'll be trying to move up a gear.''

Olympiakos defender Torosidis said his team's preparation fell short.

"I don't want to make excuses. We knew the match would be tough and it was,'' he said. "We thought we were heading for a draw, but they got the goal and we didn't make enough of our chances ... It turns out we weren't ready for the game.''