Tim Henman shrugged off fatigue to defeat both Juan Martin del Potro and Mario Ancic on the same day to reach the Japan Open semi-finals.
Henman notched up his first career win over Ancic in Japan
Rain had postponed his match against Del Porto but the Briton dug in, battling back from 1-4 in the opener to claim a 7-6 (7-3) 6-3 win.
After nearly a 12-hour wait, Henman secured early breaks in each set to wrap up a 6-2 6-2 win over Ancic.
The Briton now meets Korean Hyung-Taik Lee for a place in the final.
I can play aggressively in these conditions and that's when I'm playing my best tennis
"It's an unusual situation," said Henman. "I haven't played two matches in one day for a long time.
"But I thought I played very, very well this morning and I played even better in the evening.
"I felt very good. I think the condition of the court and the balls are really perfect for me.
"I feel like I can play aggressively and get forward to the net a lot and that's when I'm playing my best tennis."
Henman is attempting to reach his first ATP tour final since reaching the Indian Wells final in March 2004.
Argentine teenager Del Porto was on course to derail Henman's challenge as he raced to a 4-1 lead when their match finally got under way at 0900 Tokyo time.
However, Henman recovered and claimed the tie-break before breaking immediately in the second set to wrap up the match.
Ancic, who knocked Henman out of the 2004 Wimbledon quarter-finals, looked like a tricky prospect for the 32-year-old Briton.
But a tough 6-2 4-6 6-4 victory against Rainer Schuttler earlier in the day had taken its toll on the big-serving Ancic.
An in-form Henman easily moved past him and into a semi-final tie against Lee, who knocked out Spanish second seed Tommy Robredo.
Roger Federer and unseeded German Benjamin Becker face each other in the second semi-final on Saturday.
Andy Murray and his brother Jamie will kick-off the weekend's action after their doubles semi-final against Americans Paul Goldstein and Jim Thomas was postponed.