Whilst the seniors were booking their place in Brazil at Wembley, the Under-21s were thrashing Lithuania 5-0 led by a 'man-of-the-match' display by Morrison.
He was delighted with his performance, opening the scoring at Portman Road inside two minutes before adding an exquisite second in the 71st minute, and Morrison is now looking ahead to the Manchester City game.
"I'm very happy with the performance on my second game for the Under-21s," he told West Ham TV after the 5-0 win.
"My performance was good and so was the team performance and we couldn't have hoped for much better.
"No matter what game I'm going into I always get nervous. Sometimes nerves can be a good thing and they certainly were here.
"I've found it great being part of the squad, I've come in and the lads have treated me well and I've got on with everyone really well so it's been good."
Sam Allardyce's side return to action against title contenders Manchester City on Saturday - a match Morrison is confident of securing another three points from.
"I'm very excited because obviously I used to play for Manchester United, but I never played against their first team so I'm really looking forward to it," he said.
"Of course we can cause a shock. We're a great team and we should have had a lot of goals this season but for some reason we haven't.
"Against Tottenham we managed to get the goals which have been missing which was pleasing.
"The defence has been solid so if we carry on doing what we're doing we can cause an upset."