United secured their place in the Europa League final as they defeated the Italian side 8-5 on aggregate, despite losing the second leg of the match 3-2 in Rome.
Cavani netted both United goals in the Italian capital to put nerves at ease, but it was another moment in the match which might be better remembered by some fans.
In the 71st minute of the match young forward Greenwood found himself embroiled in a skirmish with Gianluca Mancini before fellow Roma player Rick Karsdorp joined in.
Momentarily it looked like things could kick off before veteran forward Cavani quickly arrived on the scene to protect his teammate, pushing away an opponent, before diffusing the situation.
Footage of the clip soon went viral on social media and now the Uruguayan forward has lifted the lid on the memorable moment.
“I’ve always said that I’m someone who works very hard in football,” Cavani told ManUtd.com. “I’m out on the pitch and part of a team to work hard for that team and to do my best for every one of the lads who go to make up our team.
“There are times when you’re out there when I believe you need to protect and stand up for one of your team-mates. Sometimes because it might be down to a lack of experience on their part, and they might make a mistake. Many times, it is because you believe that a situation that they are involved in during a stand-off just isn’t fair.
“In that incident against Roma, what I felt was that he was arguing face-to-face with the Roma defender which is something that can happen in football. The next minute, a third guy came on the scene and began pushing him when he clearly wasn’t part of the original argument. I told him he should keep out of the incident and that’s why I went to help Mason and offer him some protection.
“I also tried to separate the players so the incident would calm down. We were in a key period of the game and he could have been given a red card. I got a yellow card for my trouble, but the main thing was really to protect and defend him and to try to prevent everything escalating further.”