SHANGHAI: Rafael Nadal moved in to the semi-finals of the Shanghai Masters Friday when injured Ivan Ljubicic retired with a leg problem to hand a 3-6, 6-3 win to the top-seeded Spaniard.

Nadal expressed disappointment at the bitter ending as the veteran Croatian could not go on at an event peppered with pullouts all week, including by Wimbledon finalist Andy Roddick and US Open winner Juan Martin Del Potro.

"I'm sorry for Ivan," said the world number two, who has shared in physical problems this season. "I wish him a fast recovery.

"I know how tough it is to be injured," said the player, who missed his Wimbledon title defence due to knee problems and also needed a month to recover from an abdominal strain.

Nadal will Saturday face a surprise opponent in unseeded compatriot Feliciano Lopez, who continued on the winning streak of his season. The 28-year-old produced his best showing of 2009 for a place in the final four with an upset of ninth seed Robin Soderling 7-6 (7/4), 6-3.

"I'm happy to be in the semi-finals," said Nadal. "I'm also very happy for Feliciano.

"He's been having a difficult year and this is a big result for him. He will be coming to the court with confidence. I hope to play a good match and have my chances to win."

Ljubicic took treatment on his leg and finally pulled the plug at the start of the third set after just over 90 minutes.

Soderling, who played the Roland Garros final against Roger Federer, led 4-2 in the opening set before Lopez, 28 and ranked 41st, seized the momentum to win in 94 minutes, with three breaks of serve and 30 unforced errors by the Swede.

Frenchman Gilles Simon put up a fight before second seed Novak Djokovic struggled through into his second straight semi-final in China with a 6-3, 2-6, 6-2 win in their quarter-final.

Second seed Novak Djokovic backed up his Beijing title of last weekend as he overcame stiff resistance to advance into the last four, with Simon saving a pair of match points.

The Serb broke to start the opening set before Simon, winner of the Bangkok title last month, retaliated by taking the second. A run of breaks in the third finally ended with Djokovic taking a 4-2 lead on his way to his 66th win of the season and a semi-final spot in his fifth Masters 1000 of the season.

Nikolay Davydenko moved closer to a spot in next month's season-ending showpiece in London with a 6-1, 4-6, 6-1 defeat of Radek Stepanek in his quarter-final.

The Russian sixth seed, who missed three months of the season with injuries but has still reached a dozen quarter-finals in 2009, leapfrogged Frenchman Jo-Wilfried Tsonga and Chile's Fernando Gonzalez to stand provisional ninth in the race to the World Tour Finals.

Three places remain up for grabs in the eight-man field with a month of the regular ATP season to go.

The Russian is trying to complete the autumn Asian swing with a second title after lifting his third of the season in Kuala Lumpur a fortnight ago.

"I've had good results in Asia for three weeks," he said. "I still have three more tournaments this season. I hope I can play well (at the final Masters 1000 of the season) a Paris Bercy and defend my semi-final there."