Talk about making an impression on the new boss.
Ahead of the game, Mourinho told reporters of Alli: "I asked him if he was Dele or Dele’s brother. He told me he was Dele. ‘OK,’ I said. ‘Play like Dele.’"
And he did.
Starting in the no.10 role, with Christian Eriksen left on the bench, he regularly found pockets of space between the Hammers midfield and defence, before notching his first Premier League assist of the season as Heung-min Son broke the deadlock.
But that was only just the beginning. Minutes later, he turned and had a pop at goal - with Roberto less than convincing between the sticks - before pulling off a remarkable piece of skill.
Chasing a low ball forward, he controlled on the touchline but lost his balance, fell backwards onto the pitch but kept his composure for a Cruyff turn-esque flick while on his back to Son, who went on to assist Lucas Moura seconds later.
"That's street football," chimed Joe Cole on BT Sport. "That will go viral worldwide."
Watch the cheeky flick below...
