Opta counted the ages of coaches when they reached the milestone of 50 games in the Premier League, and listed the youngest coaches to coach 50 games in the Premier League, with Herzeler ranking first.
Ranking of the youngest managers with 50 games in the Premier League:
Herzler (Brighton) - 32 years, 269 days
Coleman (Fulham) - 34 years, 107 days
Vialli (Chelsea) - 34 years, 305 days
Gullit (Chelsea) - 35 years, 61 days
Villas-Boas (Tottenham) - 35 years, 95 days