Alexis Sanchez made his Premier League debut for Manchester United but he ended up on the losing side.
Eriksen scored the third-fastest goal in the history of the Premier League to shock the visitors, who then gifted Spurs their second as Phil Jones turned Kieran Trippier's cross into his own goal.
Alexis Sanchez made his league debut for United, but didn't have a shot at goal or create a chance - the first time this season he had been so ineffective.
"He [Sanchez] worked hard," Mourinho said. "But, again, the transformation the game had, the game was not for him and in the second half I try to give him a position where he could be more close to [Romelu] Lukaku but then he felt the need to drop too much and he was dropping too much to try to organise."