Russia’s Daniil Medvedev is two wins away from regaining the men’s world number one spot after reaching the Miami Open last 16.

Medvedev ended Novak Djokovic’s long run at the top of the rankings last month before the Serb moved back ahead.

But with Djokovic absent in Miami, the 26-year-old Russian will take over again if he reaches the semi-finals.

The US Open champion moved into the fourth round with a 6-3 6-4 win over Spain’s Pedro Martinez.