With regular left-back Patrice Evra flying home to be with his pregnant wife as she went into labour, Keane was given a chance to line-up in the United defence despite not having played the role for more than a year.
Regardless of the unexpected nature of the call-up to the starting XI, the youngster was happy with his performance, and that of the team.
"It was strange," the 19-year-old told MUTV. "I've not played there [left-back] for over a year now, but I thought I adapted quite well to the position and Rio and all the other players helped me out a lot, so I thought I did quite well.
"They've all got great experience and they're great players to play with. I grew up watching all of them and to play in the same team as them is great. I really enjoyed it."
Keane now hopes to be given a chance to take on Catalan giants Barcelona on Wednesday but insisted that he would enjoy watching United face Tito Vilanova's team even if he was not involved.
"We've only been here a day but we had a good time around the hotel and the game today was a great experience," he added.
"It [the Barcelona game] is a great occasion for everyone and it'll just be a great game to watch, never mind play in if I get a chance. I'm looking forward to it."
United captain Nemanja Vidic made his return from a knee injury in the 0-0 with the Norwegian side, and was impressed by Keane's performance in defence.
"I'm glad he's had a full ninety minutes," the Serbian said. "He was confident on the ball and it's a big change from the youth academy, obviously, and I think he did really well."