Rösner, competing in his 21st PSA World Series quarter-final, dominated world number six Elshorbagy in the third and fourth games on his way to claiming an 11-7, 9-11, 11-5, 11-3 victory at the Khalifa International Tennis and Squash Complex in Doha.  

It followed his superb last-16 win over world champion Karim Abdel Gawad of Egypt yesterday.

"This is the biggest win of my career - it has to be the biggest achievement of my life," Rösner, the world number 12, said.

"Even though I beat Karim last night, getting to the semis is the most special thing for me because I haven’t been able to reach this stage at this kind of tournament.

"To reach this stage after so many years is a great feeling, and I’m turning 30 on Sunday (November 5), so it’s just before my birthday.

"I think this is already a good birthday gift but the tournament is not over yet.

"If I play like I have done the past two days then I can get even further.

"I’m feeling comfortable here.

"I’m playing well and feeling good,

"I’m confident that I can beat these guys and I think that made a difference today."

Rösner is due to go up against world number seven Tarek Momen tomorrow for a place in the final after the Egyptian knocked out 37-year-old Nick Matthew of England with an 11-5, 9-11, 11-7, 11-6 win.

Momen's victory secures his first PSA World Series semi-final berth in three years.

The top half of the draw saw the latest instalment of the rapidly developing rivalry between Egyptian stars Mohamed Elshorbagy and Ali Farag go the way of the former.

The two players were meeting for the third tournament in succession with Farag having triumphed in last month’s US Open final in Philadelphia and Elshorbagy avenging that defeat with victory in the Channel VAS Championships in English town Weybridge a week later.

This time around it was world number three Elshorbagy who prevailed, winning 11-7, 11-4, 9-11, 16-18, 11-8 in a 93-minute encounter.

"He’s making me push that extra mile every time we play," Elshorbagy, a two-time winner and last year’s tournament runner-up, said.

"We’re going to push each other for the rest of our careers because we always play such great matches together.

"I’m really happy I got through - it was 50-50 and I’m happy I got the win in the end.

"I’m not going to be able to beat him every time, that’s just how it is and that’s the beauty of the sport.

"This has been a really tough draw for both of us.

"Neither of us deserve to go out in the quarters."

Elshorbagy is scheduled to face world number one Gregory Gaultier in the last four after the Frenchman defeated Peruvian Diego Elias 11-2, 11-7, 11-5.

The Qatar Classic is the second PSA World Series tournament of the 2017-2018 season.