The defender has been in fine form this season and apart from his error at Arsenal has looked worth the £5million United paid for him just over a year ago, but now Sir Bobby is urging him to work harder in a bid to force his way into the England squad.
"As far as Titus is concerned, it is not a question of talent because he has plenty of that. It is about his focus and application. If he gets that right he will be fine, but we're very pleased with the way he is progressing,” the manager told The Journal.
"He still needs to work on that side of his game, but we knew what we were buying when we brought him here and he is developing as a player.
"The way he passes the ball out of defence is so impressive. In fact, he is probably the best two-footed player we've got at the club.
"I remember players like Tony Adams and Sol Campbell when they were young. If I'm honest, Titus is a little behind them at the same stage, but he is getting there.
"Since he came back into the side, he has been a colossus. Even at Arsenal, where had made the mistake for the first goal, he had an excellent game apart from that.
"Against Southampton, where I thought the whole back four had a good game, he probably shaded it as the best of the bunch again.
"He was up against James Beattie, an England player, and he didn't give him a sniff all afternoon."