-After a clash of heads in the ninth minute with Southampon’s Wesley Hoedt, the £75m striker was taken off on a stretcher.
-Lukaku had hardly moved for minutes with Man United medical staff huddled around him for minutes.
-He was seen by television cameras blinking, but a doctor held his head while he was lifted onto the stretcher.
The 24-year-old was strapped in and carried off wearing an oxygen mask to a warm ovation from the Old Trafford fans.
Marcus Rashford came on to replace the Belgian forward early in the Premier League fixture.
Jose Mourinho said: “The doctor didn’t think twice about making the decision on Romelu. Because he has a problem — not just for today — but also for the next two matches I would say for sure.”
Mourinho had wanted to rest Lukaku, saying: “I was very honest with him, he was very honest with me. I said let’s go for rest but he said he wanted to sacrifice.”
After his eighth-minute injury needed five minutes of medical attention, Lukaku was further treated at Old Trafford with an ambulance on standby.