Marko Arnautovic had no sympathy for his old boss Jose Mourinho after he crowned a 3-1 win for West Ham that piled further pressure on the Manchester United manager.
Felipe Anderson opened his Premier League account with an impudent backheel and West Ham were two goals to the good by half time against their abject visitors after Victor Lindelof deflected Andriy Yarmolenko's strike past a helpless David de Gea.
Substitute Marcus Rashford briefly gave United hope but Arnautovic – who was a reported close-season target for Mourinho despite failing to make the grade under him at Inter – slotted home a third to spark joyous celebrations at London Stadium.
When asked by BT Sport whether he had a message for Mourinho, the Austria international replied: "No, nothing to say. I look at my team. We try to win games
"Whatever the other team does, and whatever problems [they have], it's their stuff, not our stuff."
Arnautovic was back in Manuel Pellegrini's side after being sidelined by a knee problem that captain Mark Noble revealed limited his time on the training pitch this week.
"Marko hasn't trained much," he told BT Sport, having slid the pass through for Arnautovic's fourth Premier League goal of the campaign.
"We know he's been injured. To perform like that and run like he did shows you he's working hard for the team."
Noble added: "That performance was fantastic for the fans. They've seen a couple of bad ones this season but there's been three now that have been really good."
