Thievy's goal only seconds into his debut could not prevent Albion slipping to a 3-1 defeat at Crystal Palace.
Pepe Mel made three changes to the side that drew 1-1 with Liverpool with James Morrison, Victor Anichebe and Craig Dawson recalled.
Debutant Thievy started on the bench but came on with Albion already 2-0 at half time. The Frenchman scored 40 seconds into his debut to pull a goal back but Palace were awarded a controversial late penalty to kill Albion off.
But who gets your vote for Man of the Match?
Claudio Yacob won the Liverpool accolade with 37.2% of the votes.
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