The young defender played his first game in more than six months as United faced Paris Saint-Germain in the UEFA Champions League group stages.
The 22-year-old was nearly faultless as he handled the likes of Kylian Mbappe and Neymar for 90 minutes.
"All Axel has got to do now is play games, stay fit, play games, because he's got all the attributes," Giggs told Webby and O'Neill.
"He can handle the ball, he can even play midfield, we thought about playing him in midfield when he was fit under Louis [Van Gaal].
"He can read the game well, he's quick, I think he showed that yesterday [against PSG].
"But he's got to play games. And when he plays game his confidence will grow because he's got all the attributes to be a Man United centre-half.
"Now he's just got to bang out those games. Once he does that it's up to him to say to Ole, 'leave me out of the team, I'm doing so well you can't leave me out of the team'."