Ole Gunnar Solskjaer praised his players for showing "the magic" in a 9-0 win over Southampton Tuesday night.
United equalled their best-ever Premier League win (matching their 9-0 victory over Ipswich in 1995) at Old Trafford and were helped by an early sending off for the away side.
Alexandre Jankewitz was sent off after just 79 seconds, but Solskjaer was pleased they could break their way through Ralph Hassenhuttl's defense.
"We shared the goals between the players," said Solskjaer. "When the game starts like it does, it's always if you can get the first goal as we have seen so many examples of 10 men closing up shop and getting a draw. We've been waiting for them to show the magic, and it was a night for them to go and enjoy it. We've not had many times where we could just enjoy the second half.
"You get lots of confidence from a performance like this. Scoring goals is always good for a team. Confidence is one thing, but it was about the mojo and spark, the X factor," continued Solskjaer. "Mason Greenwood was terrific, and his performance was top for a player who did not score a goal."
The Norwegian was happy to see Anthony Martial get on the scoresheet again after some underwhelming performances but praised the whole side.
"Anthony Martial, it is good to get him going," Solkkjaer said. "He could have had another one with the chip. Unfortunately, it did not go in but a good performance from everyone. You have to take your chances in tight or open games. You never know what might be the deciding factor. We know better than anyone what goal difference can do to you because we have lost the league on goal difference."