Söderling squandered four match points in the third set before outlasting Austria’s Andreas Haider-Maurer 7-5, 6-3, 6-7 (2/7), 5-7, 6-4 after three hours and 52 minutes.
Haider-Maurer, a 23-year-old who fired 34 aces past the first top-10 foe of his career, nearly made Soderling pay for not finishing him early in the afternoon heat.
“It was a tough match in tough conditions,” Soderling said. “It’s better to win it in five than lose it in five.”
Söderling fell behind 4-1, but won six of the last seven games in the first set and seized a 4-1 edge en route to taking the second set as well.
Haider-Maurer saved four match points in the third set and jumped to a 6-1 lead in the tie-break to force a fourth set. When Söderling netted a forehand smash to surrender a break and the fourth set, he was pushed to the brink.
“Definitely I had a strong chance,” Haider-Maurer said.
Söderling broke in the fifth game of the final set and served out for the triumph, although Haider-Maurer hit 58 winners to Söderling’s 44 and made 65 unforced errors to 74 by the Swede, who felt fine despite the endurance test.
“I feel pretty good physically. I had almost four good hours of practice. That wasn’t so bad,” said Söderling. “I can play better. I’ve played worse.”
Next in Söderling’s path to his first US Open semi-final is American Taylor Dent, who ousted Colombian Alejandro Falla 6-4, 7-5, 6-1.
“I think I’ve showed that I can go very deep in every Grand Slam,” said Söderling. “But you’ve to play well. I can’t just go on court and not fight and not play well. Then you will lose.”
Söderling is the highest-ranked obstacle in second seed Roger Federer’s path to the semi-finals. French Open runner-up Söderling knocked off Federer in the Roland Garros quarter-finals, ending the Swiss star’s run of 23 consecutive Grand Slam semi-final appearances.