Roger Federer's eagerly-anticipated return to the Italian Open ended in disappointment as the Swiss star was forced to withdraw ©Getty Images

Roger Federer's eagerly-anticipated return to the Italian Open ended in disappointment as the Swiss star was forced to withdraw from the tournament in Rome with a leg injury.

The Swiss star, a 20-time Grand Slam champion, had been due to face Stefanos Tsitsipas at Foro Italico.

But the 37-year-old was unable to play after suffering an injury in his last-16 encounter with Portugal's Joao Sousa yesterday.

"I am disappointed that I will not be able to compete," Federer said.

"I am not 100 per cent physically and after consultation with my team, it was determined that I not play.

"Rome has always been one of my favourite cities to visit and I hope to be back next year."

Spanish second seed Rafael Nadal beat Fernando Verdasco to reach the semi-finals ©Getty Images
Spanish second seed Rafael Nadal beat Fernando Verdasco to reach the semi-finals ©Getty Images

Tsitsipas will face Rafael Nadal in the semi-finals in a repeat of their clash at the Madrid Open, where the 20-year-old inflicted a shock defeat on the Spanish clay court specialist.

Nadal booked his place in the last four with a comprehensive 6-4, 6-0 win over fellow Spaniard Fernando Verdasco.

The women's draw has also been hit with a high-profile withdrawal as world number one Naomi Osaka pulled out before her quarter-final with Kiki Bertens of the Netherlands.

The Japanese player, who recorded consecutive 6-3 6-3 wins over Dominika Cibulkova and Mihaela Buzarnescu on Thursday, retired with a hand injury.

Bertens, winner of the Madrid Open earlier this month, has secured a place in the semi-final by virtue of Osaka's withdrawal.