The Red Devils extended their unbeaten run in the Premier League to seven games and have moved to third position with the win over their old rivals.
A flying start from the hosts was rewarded with two quick goals in the opening three minutes thanks to midfielder Scott McTominay’s brace, before Bruno Fernandes made it three inside 20 minutes.
Victor Lindelof converted at the far post after Anthony Martial flicked on a corner to make it four on the 37th minute mark, but the hosts had a glimmer of hope when Liam Cooper's header pulled one back on the cusp of halftime.
Solskjaer’s men restored their four-goal lead midway through the game as Daniel James fired a shot through the legs of goalkeeper Illan Meslier.
Fernandes got his second from the penalty spot four minutes later before Leeds got another consolation. Stuart Dallas curled a beauty into the top right corner for 6-2.
"What a game of football. Unfortunately, there was no crowd to watch it. This will go down as one of the great Manchester United v Leeds games,” Solskjaer said after the game.
"We had to start properly. We know we’re playing against a team with a certain style and we needed to match them physically.
"It wasn’t a bad start. Scotty showed he was a striker when he was a kid. He’s got it in him. He’s such a strong boy physically. He was a striker before so he knows where the goal is.
"Leeds play the same way whether they’re 4-0 up, 4-0 down or at 0-0. They do that every three days, every game. You have to run until the whistle goes.
"Our fitness is getting better. We were lacking that at the start of the season but now we’re looking stronger. I think the boys did fantastically well.
"It’s one third of the season gone. You can’t start talking about league positions. We’ll keep carrying on, working hard. Maybe when we get to March or April we can take a look [at the table]."
