By Terry Daley
ROME (Reuters) - Novak Djokovic stayed on course for his third Rome Masters title although he was forced to dig deep to beat a tenacious David Ferrer 7-5 4-6 6-3 in a high-quality quarter-final on Friday.
The Serb looked to be in full control when he led 5-2 in the opening set but Spaniard Ferrer fought back to 5-5 and although he lost the opener the tone was set for an intense duel.
Djokovic eventually prevailed on his second match point having double-faulted on his first, the point in between being a 38-stroke baseline rally of extraordinary quality.
Djokovic will face Milos Raonic in the semi-finals after the Canadian beat Roger Federer's conqueror Frenchman Jeremy Chardy.
On the other side of the draw Grigor Dimitrov reached his first masters Series semi-final when German veteran Tommy Haas retired from their match with a shoulder injury.
Celebrating his 23rd birthday Dimitrov was presented with a cake on the court which his coach Roger Rasheed splatted all over the Bulgarian's face.
"It was one of the most memorable days of my life," said Dimitrov. "I was just talking to my team, it's my first win on my birthday, so it feels good. It's a bit unfortunate, the way it ended up. But I'm just a happy birthday boy today."
Top seed and defending champion Rafa Nadal faces Briton Andy Murray in the night session.
In the women's Italian Open at the same atmospheric Foro Italico venue top seed Serena Williams breezed past Shuai Zhang 6-1 6-3 in a one-sided contest.
The American roared out of the traps, winning five games in a row and crushing any chance of resistance from the Chinese.
Zhang raised her game towards the end of the first set and made a decent fist of the second, but Williams's driving forehand and serving power was too much for the world number 43.
Williams will get the chance to avenge her Australian Open defeat to Ana Ivanovic in the semis after the Serbian 11th seed followed up her impressive win over Maria Sharapova with a thrilling 6-4 3-6 6-4 win over Spain's Carla Suarez Navarro.
Home fans were given something to shout about when Sara Errani reached the semi-finals with a superb 6-3 4-6 6-2 victory over world number two Li Na - her first career win against a player ranked in the top three.
Djokovic, seeking a 19th Masters Series crown, was never given a moments rest by Ferrer once the hustling Spaniard got into his stride, but at 3-2 in the second set he looked on course to finish the job in straight sets.
Then a brief spell of rain halted play and on the resumption Ferrer broke Djokovic's serve and went on to lock up the second set and force a decider.
Again the Serb forged ahead but Ferrer refused to be subdued by the more powerful Serb, scrambling back to 3-3.
Ferrer then had a sniff of a chance in the next game, missing a golden opportunity to eek out some break points at 15-30, but Djokovic held firm and then broke to lead 5-3.
Djokovic wobbled on his first match point, serving a double-fault but he was not phased and went on to win a punishing baseline exchange in the next point and claimed victory when Ferrer hit a tired-looking backhand wide.
(Editing by Martyn Herman)