Manchester United playmaker Henrikh Mkhitaryan is surprised that Chelsea allowed a player of talent like Nemanja Matic to join their direct rivals United.

The Serbian, who has joined United in a £40m move, was arguably the best player on the pitch as the Red Devils defeated West Ham 4-0 in the season opener on Sunday.

"Actually, I am [surprised]," said Mkhitaryan after the game.

"But I'm very happy that we've got him."