Naomi Osaka and Simona Halep progressed to the third round of the Madrid Open on Tuesday, but Angelique Kerber was forced to withdraw after twisting her ankle.

Fourth seeded German Kerber suffered the injury in practice on Tuesday, with her scheduled opponent Petra Martic qualifying automatically for the next phase.

Kerber had been one of the favourites to battle world No.1 Naomi Osaka for the title in the Spanish capital this week and had a chance to overhaul the Japanese at the top of the rankings.

The ankle injury is another setback for 2018 Wimbledon champion Kerber, who missed two weeks of the claycourt season after picking up a virus in Monterrey last month, and she set her sights on returning in time for next week’s Italian Open.

“I think it’s the worst [clay court preparation] I ever had. I was really looking forward to this year,” said Kerber.

“Hopefully I can be ready for the next big ones. I hope there’s a big chance I can play in Rome [next week].”

Osaka struggled to see off Sara Sorribes Tormo in three sets, taking two hours 36 minutes to win 7-6 (7-5) 3-6 6-0.

The two-time grand slam winner put in an inconsistent performance before overpowering the Spaniard in the third set, regaining her ruthless touch.

Two-time Madrid champion Halep eased to a 7-5 6-1 win over Britain’s Johanna Konta.

The Romanian world No.3 will face Slovakian Viktoria Kuzmova in the third round.

Belarusian Aliaksandra Sasnovic also progressed, beating Slovakia’s Anna Schmiedlova 6-2 6-2.