Top seed Rafael Nadal worked double time to beat Dutchman Peter Wessels 7-6, 6-2 on Friday, setting up a China Open semi-final with fellow Spaniard Juan Carlos Ferrero.
Sixth seed Ferrero won 6-2, 3-6, 6-3 after a battle of attrition with number three David Nalbandian in their quarter-final.
French Open champion Nadal had already taken more than 2-1/2 hours to beat American Justin Gimelstob 5-7, 6-4, 6-4 in his rain-delayed second round match earlier on Friday.
But the world number two looked more comfortable on the Beijing hardcourts in his quarter-final, quickly putting Wessels out of his misery after taking the first set tiebreak 7-3.
"I played for four hours today so I'm a bit tired but I'm confident I can win tomorrow," said Nadal, who has won all three previous meetings with Ferrero, all on clay.
"I played really badly this morning but I'm happy with the improvement I made this evening. Ferrero is a great player but I don't fear him."
The 19-year-old Nadal, who improved his record for 2005 to 70-10, is bidding to win his 10th title of the year on his first visit to Asia.
CORIA'S OVERTIME
Argentina's Guillermo Coria also put in overtime as the second seed knocked out last year's runner-up Mikhail Youzhny 6-4, 1-6, 6-1 to advance in the bottom half of the draw.
Coria will take on Sweden's Thomas Johansson in Saturday's semi-finals after the fourth seed's 7-6, 6-3 dismissal of Spain's Carlos Moya.
World number eight Coria had trounced Japan's Toshihide Matsui 6-1, 6-0 in Friday's first match after rain showers wiped out the entire day's play on Thursday.
Ferrero prevailed after a dour baseline struggle, breaking Argentine Nalbandian to go ahead 5-3 in the third set and closing out with a big serve on his first match point.
"I lost both times I played Nalbandian before, but they were close matches," said Ferrero, seeking to return to the top of the game after an injury-ravaged 2004. "Today I was very solid.
"I missed so much of last season. It's like I'm starting my career again. I'm confident I can get back into the top 10 soon."