The first half was very close.
But just as it was, after just over half an hour, the lightning-quick 22-year-old ran through the West Ham defence, poked past goalkeeper Alphonse Areola and was brought down.
Sentenced penalty, and who but Haaland himself would take care of it.
He stepped forward and rolled the ball into the left corner, via the post, to make it 1-0.
In the second half, home team West Ham wanted to start the hunt for an equaliser.
It meant more players pushed up offensively and large gaps at the back when the ball drop did come.
On one of those occasions, Kevin De Bruyne showed his brilliance as he found Erling Haaland with a perfectly balanced through ball.
Haaland turned his body up and coolly slotted in 2-0.
After that, the air went out of West Ham, who did not really succeed with a final effort.