Kirk Broadfoot spoke of his horror at witnessing the injury which could rule Antonio Valencia out for the season and wished the Manchester United player a quick recovery.
Valencia went down after a seemingly innocuous incident involving the Rangers full-back and immediately signalled he was in trouble. TV replays showed his foot pointing in the wrong direction and he was eventually taken off on a stretcher, with Broadfoot in obvious distress.
"I'm not too sure what happened," he admitted. "I just slid in and looked round and his bone was sticking out. We tried to get the physio on to help him because you don't like to see that."
He added: "These things happen and hopefully he makes a fast recovery. I've never seen anything like that so close before.
"You see things like that on television and it's not good but to see it there in front of you, it doesn't look nice and I just hope he recovers quickly."
Sir Alex Ferguson revealed after the goalless draw with the Scottish champions he fears Valencia will be out for the rest of the season.
"It is a dislocation or a fracture and he gets operated on tomorrow (Wednesday) morning," he said.
"It was an innocuous challenge but when you saw the Rangers player waving, you knew it was a bad one.
"It is a bad blow for the boy. It is similar to the injury Alan Smith got and you are talking about the rest of the season."