England's world number one James Willstrop survived his third consecutive Delaware Investments US Open match lasting more than 80 minutes when he beat eighth-seeded Egyptian Mohamed El Shorbagy in the quarter-finals of the PSA World Series event at Drexel University in Philadelphia.

Helped by a series of errors from his 21-year-old opponent, the experienced Willstrop (pictured above in Philadelphia action) took the first game - but El Shorbagy stepped up the pace, cutting down the errors, and for the next three games there was little to choose between the two.

After world No8 El Shorbagy levelled the match to force a decider, the English favourite's superior control and physical conditioning started to pay dividends and Willstrop raced to a stunning 10-0 lead.

At ten match-balls down, El Shorbagy finally found a dropshot to prevent a whitewash - and raised his arms, screaming "yes", to the delight of the crowd.

Four more points, all from crisp winners followed, and thoughts started to turn to the impossible comeback.

But a loose shot, resulting in a stroke, put paid to those hopes and a relieved and tired Willstrop was through to his fourth successive US Open semi-final after his 11-6, 7-11, 12-10, 8-11, 11-5 triumph in 90 minutes.

"I had a good first, but then he started playing at a really good pace and I was failing to take the chances I gave myself at the front," said the 29-year-old from Leeds later. "I was a bit weak and tentative in that area and that helped him.

"I was pleased with the fifth, mentally and physically, but when he starts coming back hitting winners you just have to play your game and not panic. If he'd made it, you'd have to take your hat off to him, but it was unlikely.

"I'm pleased to get through a match like that, and the format of this tournament - with split first round and quarters - is best for the players, so I'll be able to get a bit of recovery tomorrow."

Willstrop will face career-long French rival Gregory Gaultier for a place in the final. The third seed from Aix-en-Provence was facing fifth-seeded Egyptian Karim Darwish for the 16th time on the PSA Tour since 2007 - but the first since both became fathers for the first time recently.

After too many errors in the game, Gaultier recovered to find improved consistency in the second and proceeded to dominate the rest of the match - showing determination when necessary as well as his renowned shot-making skills to win 6-11, 11-5, 11-5, 11-4 in 61 minutes.

"I struggled at the beginning," admitted Gaultier, who now meets Willstrop for the first time since their epic 118-minute British Grand Prix semi-final last month.

"I had the wrong strategy, going to the front too soon and he dominated me. I changed my tactics completely at the start of the second, tried to push him to the back and take things on the volley as much as I could and it paid off.

"I'm happy to play James again. We had an unbelievable match in Manchester and I'm looking forward to trying to get my revenge."

Quarter-finals (top half of draw):
[1] James Willstrop (ENG) bt [8] Mohamed El Shorbagy (EGY) 11-6, 7-11, 12-10, 8-11, 11-5 (90m)
[3] Gregory Gaultier (FRA) bt [5] Karim Darwish (EGY) 6-11, 11-5, 11-5, 11-4 (61m)