But Cavani fired home a stunning leveller early in the second half, before tapping home from close range.

The 34-year-old was then taken down for the penalty scored by Fernandes and, after Paul Pogba headed home, provided a superb pass for substitute Mason Greenwood to make it six.

"We want to go through, of course," Solskjaer said. "Good reaction at half-time

"I thought we played some good stuff in the first half as well but we forgot you have to run back as well and you have to run back quick.

"The second half we did that part better and of course that creates more opportunities to attack.

"Edinson was excellent, as a centre forward should be playing – running the channels, being a focal point, creating chances for others, scoring goals, missing a couple of chances as well. Absolutely delighted with him."

Cavani's future is subject of widespread speculation as the Uruguay internationals considers returning to South America after a challenging first season at Old Trafford.

The former Paris St German striker signed on a one-season deal in October with an option for a further year, which Solskjaer has not given up on him taking up just yet.

"He was out for seven months and he'd not been playing football for a long, long time before he came to us," Solskjaer said.

"He's had his couple of injuries and he's now worked really hard to get back fit and he shows his qualities.

"He knows my feelings. He knows that I'd love to him for another year.

"We have spoken about it. I understand this year has been very difficult but I've promised him that Old Trafford and Manchester is a different place with our fans in the stadium.

"He must try to get that feeling, to be on our side. Manchester is a fantastic place to live.

"I'm doing my best so let's see. Of course nights like this, hopefully we can get to the final and hopefully he can see himself being here for another year."

Roma left the pitch crestfallen after their almighty collapse at Old Trafford, where their three first-half injuries took their toll in a dramatic first leg.

Head coach Paulo Fonseca said: "It's a heavy defeat. We had a good first half but we didn't exist in the second.

"It's difficult to explain how the same team that did so well in the first half had that kind of second half.

"It's hard to play against a side like United without having the substitutions (to make in the second half)."

Fonseca also felt the decision to award the penalty that made it 4-2 was key, claiming Solskjaer agreed that ex-United defender Chris Smalling's challenge on Cavani did not warrant a spot-kick.

"Even the Manchester United coach was very honest and didn't think it was a penalty either," the Roma boss said. "I really didn't think it as a penalty.

"It was a decisive moment in the game and it was tough to take."