The 21-year-old, who signed for the Reds from Swansea City on 12 June, made his first appearance in a United shirt and looked lively down the wing during the first half when he attempted to create chances against Perth Glory.
He was rested for the second period as Ole Gunnar Solskjaer replaced his entire line-up, enabling the Wales international to take it all in as the Reds ran out 2-0 winners in front of more than 50,000 fans from 41 different countries at Optus Stadium.
“It's been amazing,” James told MUTV's Mark Sullivan after the game.