Sytchev completed a sweeping move from midfield with just four minutes gone, stroking the ball past Austria keeper Thomas Mandl to put his side in command of the UEFA Champions League third qualifying round tie.
Sytchev close again
Three minutes after opening the scoring, the Russian was within inches of doubling the lead but his shot flew past the upright. Austria responded to Marseille's blistering start by creating two great openings in an enthralling five-minute spell.
First Sean Dundee's rasping drive forced a good save from Vedran Runje in the visitors' goal. Then Krzysztof Ratajczyk's header flew just wide of the post.
The French side dominated the remainder of the game and could have scored more, notably when Sytchev's 62nd-minute shot was well saved. After the game Marseille coach Alain Perrin admitted his side deserved the win.
'We played well'
"I thought we played well and am delighted with the win," said Perrin. "I expected Austria to put on a better show but they seemed to have a bad day. I think they will be tougher to beat in the return leg but if we play as we did today we should go through."
©UEFA.com 1998-2011. All rights reserved.