Brentford Women B were defeated 2-0 by South London in their first Greater London Premier Division fixture on Sunday.
Goals in both halves saw South London earn the three points, in what was new head coach Yannawit Khantharat's first game in charge.
The newly-promoted Bees struggled to make any real impact in their opening-day defeat, with the visitors pushing forward from the first whistle.
Freya Walker, who was in between the posts for Brentford, made a couple of really good saves inside the opening 20 minutes of the game.
Just before the half-hour mark South London took the lead after winning the ball in midfield before finishing a well-worked move.
Brentford’s only real chance of the half came when Rebekah Edwards ended a brilliant run with a pass to Ruby Huxley, but her shot was well saved.
The Bees continued to be pinned back in their own half in the second period with South London doubling their lead on 60 minutes.
The home side made a number of changes in the second half with hopes of finding their way back into the game.
Chelsie Berry was one of the players who was introduced to the match on 70 minutes and almost made an instant impact.
Berry did well to beat her marker as she drew in another player with a great run, before being brought down with the resulting tackle ending in a red card for South London.
With 15 minutes to play the hosts got bodies forward as they searched for a goal which would get them back into the match.
Chelsey Logan made a good impact from the bench after returning from injury, but South London defended their box well.
The visiting side saw their lead out with 10 players on the pitch, collecting the three points on the opening day.
Brentford Women B: Walker, Ali, Henry, Redman, McPherson-Maraj, Abou-Abdallah, McComb, Wood, Mckenzie, Hawkes, Foley
Subs: Briscoe, Berry, Huxley, Edwards, Logan