That trio is likely to start on the bench against Tottenham, with Anthony Martial, Marcus Rashford and Jesse Lingard seemingly Solskjaer's preferred front three.
But just how good were the performances from the second-string side?
But it wasn't plain sailing for Lukaku, and the Belgian did struggle for most of the first half. He came on after 62 minutes to replace Juan Mata and overall he did well. Understandably, then, United were playing with the full extent of their abilities - but there were still some reasons to worry.
Solskjaer has already warned his men that, despite their winning run, the mid-season trip to Dubai will be anything but a relaxing break.
Ole Gunnar Solskjaer has instilled a new sense of attacking freedom and belief in a squad that, in truth, should never have been 19 points behind league-leading Liverpool after the halfway mark.
Who should United sell this January? This was United's fifth game under the Norwegian and their fifth victory.
While the FA Cup is said to be losing its magic, the third round still represents an opportunity for some younger players to make their professional debut. When you have players like we have, that's how we played with Andy (Cole), (Dwight) Yorkey, (Ryan) Giggsy and Becks (David Beckham) down the sides.
Alternatively, Angel Gomes may hope to start out wide, after making his first Premier League appearance of the season against Huddersfield on Boxing Day.
Pogba was on the receiving end of a heavy challenge from Jonjo Shelvey during the 2-0 win over Newcastle on Saturday and may be ruled out of the third-round tie at Old Trafford on Saturday lunchtime.
"He's been out a month now, he's had 20 minutes against Newcastle, half an hour maybe". Mata was fouled just as he took the ball down and Fred, who tucked the ball home, was offside.
Mata dispatched a cool penalty - his first FA Cup goal since the victorious final of May 2016 - after referee Stuart Atwell penalised Omar Richards for a foul on the Spain global after a VAR consultation, with Fred's strike having been disallowed for offside in the same move. After a lengthy delay as VAR was consulted, a penalty was awarded and Mata stepped up to put United 1-0 up.