The 21-year-old defender's last outing saw him substituted at half-time against Everton after a below-par display, but he bounced back in style with a fine showing in the final half hour.
"[After the Everton game] I spoke with the players and the manager said: 'Well, you've got to learn from things like that,' Simpson told MUTV.
"It didn't go too well and it's a test of character. Some people fold. You can hide or get on with it and prove next time that you're a United player and you can do well for the team."
Simpson twice came close to opening his goalscoring account with decent shots, only to be foiled by Shay Given and a deflection respectively.
"I feel on top of the world at the moment, I'm just a bit gutted I didn't score," he admitted. "I was a bit disappointed with the first one, I thought it had gone in but I turned round and he'd got a touch.
"The second one, I just tried to get a clean strike on it but it was just a bit unlucky. How many chances do I need? Wayne said that every time I play he seems to be setting me up, but if I keep making the runs when I'm playing, surely it'll come soon."