Mkhitaryan was named in the starting XI for only the second time since his July arrival from Borussia Dortmund and gave a performance that featured six shots and three chances created as United took a huge step towards the knockout stages.
The Armenia international has been out of favour under manager Jose Mourinho but believes his lively showing on Thursday could act as a fresh beginning.
"It was a pleasure to play again and start the game," Mkhitaryan told BT Sport.
"I try to do my best and it's a very good result.
"It has been difficult to watch the team from the sidelines but you have to have passion and work hard.
"I hope it is a new start for me."Schweini offered escape route
Phil Jones made his third successive appearance for United and the centre-back explained how the team's pressing game was key to their impressive victory.
"It was a tough game, especially in the first half," Jones told MUTV. "They pressed us well and created a good chance that they could have scored from.
"But I think we played better in the second half, we were more aggressive in our pressing and we got the four goals. It was a good performance in the end.
"I think it was just a matter of time and not allowing them to play out from the back.
"Once we did that, you saw in the second half in the chances we created we caused them all sorts of problems."