The most impressive thing about Rozier last night was his defense. He, in combination with Al Horford, made Walker uncomfortable in the pick-and-roll game. Walker still had a decent game, but that's what great offensive players do.
You could definitely argue Rozier just outplayed an allstar starter last night on both ends of the court.
Rozier outplaying whoever he is matched up against as a starter is starting to become a theme. He's done that to George Hill, Eric Bledsoe, Kemba Walker, De'aron Fox, Kyle Lowry, Jrue Holliday, Ricky Rubio, D'angelo Russell, and more over the past two seasons.