Egypt's Karim Gawad surprisingly relinquished his squash world championship crown when he lost to Marwan Elshorbagy, his sixth-seeded compatriot, in the quarter-finals on Friday.

Elshorbagy's 11-8, 11-5, 11-9 success was reward for a well-disciplined ability to play tightly and accurately, and for making good choices about when to attack Gawad.

The approach denied opportunities to one of the most dangerously offensive players, and helped Elshorbagy gain a psychological edge after grabbing a close first game.

Gawad seemed increasingly bothered by a shin injury, causing him to take a three-minute timeout between the second and third games.

The respite may have helped him peg back a four-point deficit to 7-7 in the third, and save two hectic match points before Marwan found a drop shot and volley kill combination which completed his stunning victory.

"I had to work to keep my focus because I lost it for a little while," said Elshorbagy.

"I'm very happy about this but Karim took an injury break so I hope it's nothing serious."

Gawad claimed he had had shin problems since the tournament began and tried to adapt by keeping the ball tight to the back more often.

But though he rarely found his best attacking flair, he made no excuses.

"I had a plan and always believed I could win -- but Marwan was very sharp and didn't give me a chance," he said.

Elshorbagy next plays another Egyptian, Ali Farag, the US Open champion, and if he wins again, might face his elder brother, Mohamed Elshorbagy in the final.

No brothers have yet contested a world final.

Earlier Farag made another piece of history as he joined his wife Nour El Tayeb in the last four of their respective championships -- the first time a married couple have achieved this.

Farag secured a cleverly-taken 5-11, 11-6 11-3 11-6 victory over Miguel Rodriguez of Colombia.

Farag and El Tayeb made history at the US Open in October by becoming the first married couple in any sport to win major titles simultaneously.

Egypt has six of the eight semi-finalists and increased its stranglehold on the women's event when Raneem El Welily beat Malaysian legend Nicol David, the record-breaking eight-time world champion 11-8, 8-11,11-6, 11-6.

Source: AFP