James, who arrived from Swansea City for an initial £15m fee, was named in Ole Gunnar Solskjaer’s starting XI for the pre-season friendly against Perth Glory.
He caught the eye on the wing, demonstrating his electric pace and crossing ability.
James’ performance impressed Manchester United fans so much that his name began to trend on Twitter.
One fan wrote: “Dan James is going to be a complete nightmare to defend against isn’t he?
“He’s had about 4/5 runs ignored so far but he keeps sitting on the last man and runs in behind, so dangerous.
“Great pressure out of possession too, setting the tone for the others so far.”
A second said: “Dan James is sublime uno. Ellie scouting. He’s cute too, will have topreds giving him the Lindelof treatment.”
A third commented: “I’m not one to overreact but after watching him for 5 mins, I can confidently say that Dan James is going to a superstar!”
While a fourth joked: “2 minutes in and I’m convinced Dan James is the missing piece in the United jigsaw and I’m sorry to say that we’re winning the Premier League this season.”
And a fifth said: “Dan James is already my favourite player.”
The game was goalless at half-time at the Optus Stadium.
James was taken off at half-time as Solskjaer made a string of changes at the break.
Marcus Rashford, who came on for Anthony Martial, opened the scoring in the 60th minute after a sublime piece of skill from Paul Pogba.
Fellow substitute James Garner added the second late on.
Inter Milan target Romelu Lukaku missed the game due to injury.
United are back in action on Wednesday against Championship club Leeds United.