Lorient coach Christian Gourcuff is not convinced Gabriel Obertan will be a success at Manchester United.
United's new signing had a dismal loan spell at Lorient last season.
"He certainly has some talent, but also some gaps (in his game)," Gourcuff, whose son Yoann is the playmaker for France and Bordeaux, told Europe 1.
"I hope he will succeed, but he will have to make the step up mentally."