Roger Federer became the oldest world number one in tennis history after he beat Robin Haase at the Rotterdam Open.
The 36-year-old replaces Rafael Nadal, 31, at the summit, as the Spaniard recovers from a thigh injury.
Federer’s prospects looked slim when he lost the first set, but he dropped just two games thereafter to claim a 4-6 6-1 6-1 win and reach the semi-finals.
The 20-time Grand Slam champion will face Italian Andreas Seppi or Russia’s Daniil Medvedev in the last four.
