Rashford was denied from the penalty spot in the 29th minute but quickly followed up to double the lead seconds later - the England striker deftly settling a Daniel James long ball and coolly slotting past Krul for his 50th goal in all competitions for the club.
Both penalties were awarded by VAR, which also played a huge part in Arsenal's draw with Crystal Palace, while the system caused controversy on Saturday when it was used to award Brighton and Hove Albion a spot-kick against Everton.
"However, then we get someone who sits somewhere and says they are penalties".
Martial, though, made good on his miss for United's third and final goal of the day - the France global working a tidy one-two with Rashford before scoring from a tight angle in the 73rd minute.
"The second one is [a penalty] but both should be retaken, the goalkeeper is a yard off his line". I don't think he'll be back, maybe for Sheffield United after the global break, but probably it will be December before we can see him. It started with a decent performance against Liverpool and now two wins away from home.
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Parker denied that his departure had anything to do with the various scandals plaguing the company under his leadership. During his tenure, the company's market capitalisation has more than tripled.
Without a truly creative midfielder in United's trio, they relied on fluidity with Fred, McTominay and Andreas Pereira to weave their way through midfield, although some sloppy Norwich defending made the task significantly easier.
"Tim is great", he said.
"I hope it's not too bad".
The Frenchman was pictured in Dubai this month undergoing rehabilitation treatment while wearing a protective boot on his left foot and subsequent scans have revealed that the problem needs time to heal. He was a bit concerned because it was the same knee he had the ACL damage earlier in his career.
Jamal Lewis was substituted at half-time with an illness, while Emiliano Buendia suffered a knock to his shin, the Canaries boss said.