who become the oldest atp world number one
List of ATP number 1 ranked singles tennis players Lleyton Hewitt is both the youngest world No. 1 (20 years, 268 days) and youngest year-end No. 1,[10][11] while Rafael Nadal is the oldest year-end No. 1 (31 years, 211 days). Roger Federer is the oldest No. 1 (36 years, 314 days).[12]