World number one Rafael Nadal stormed into the semi-finals of the Madrid Masters on Friday with his 17th consecutive win over Tomas Berdych, 6-4 6-2.

Maria Sharapova also booked her place in the last four of the Madrid Open with a three-set win over Li Na, but top seed and reigning champion Serena Williams was forced to pull out of the tournament due to a thigh injury.

Despite coming into the tournament with doubts following surprise defeats to David Ferrer and Nicolas Almagro in recent weeks, Nadal has looked in fine form in the Spanish capital as he has cruised into the last four without the loss of a set.

“I just managed to go over the barrier of the quarter-finals against a difficult opponent which I haven’t done for a couple of weeks so I’m very happy abut that,” said Nadal.

“Now I just need to make that effort once more tomorrow. I have to keep on going on in the manner that I have so far this week, which means getting better a little each day.”

The 13-time Grand Slam champion will meet compatriot Roberto Bautista Agut or Colombia’s Santiago Giraldo on Saturday for a place in the final.

Williams was due to face Petra Kvitova in the quarter-finals but pulled out due to a thigh injury she had been carrying since sweeping aside Swiss teenager Belinda Bencic in the first round on Sunday.

“It happened during my first round match. It started to get better, but most importantly right now, I just need some time to rest and recover,” Williams said.

However, the American insisted that she will try to defend her title at the Italian Open in Rome next week.

Sharapova has been beaten by Williams in Madrid the past two years, including in the 2013 final, and the Russian is now the favourite to clinch her first title in the Spanish capital as she edged a thrilling match against second seed Li 2-6 7-6 (7-5) 6-3.

“It was just a matter of a few points in the second set and in the third, although I was up a break throughout the third set, you know she’s not going to let go. I didn’t win the match until the last point was played,” admitted Sharapova.

The four-time Grand Slam champion will face third seed Agnieszka Radwanska in the semi-finals after the Pole overcame French qualifier Caroline Garcia in three hard-fought sets 6-4 4-6 6-4 after nearly two-and-a-half hours on court.

Also into Saturday’s semis is fourth seed Simona Halep as she set up a meeting with Kvitova thanks to a 6-2 6-2 thrashing of Serbia’s Ana Ivanovic.