Paul Coll, right, is through to the Black Ball Squash Open semi-finals after Joel Makin succumbed to injury ©PSA

World number two Paul Coll of New Zealand progressed to the Black Ball Squash Open semi-finals after Wales' Joel Makin was forced to retire due to an adductor injury despite holding a 2-1 lead in Cairo.

Makin looked comfortably in control as he took a quick 2-0 lead and put himself on the verge of a semi-final place at the Professional Squash Association (PSA) World Tour Gold event but required attention from a physio at the start of the third game.

The world number eight returned to court but as Coll won 11-9, he decided that he was unable to continue.

"It’s horrible, he was playing really well," said Coll.

"He was super aggressive, he had a 2-0 lead and then you could see he wasn’t moving properly in the third.

"I was struggling to find my game on court today and he was sharp.

"I felt a bit unlucky in the second, but it’s just horrible to see him go off like that."

Coll is set to face Egypt's Marwan ElShorbagy in the final four after he overcame compatriot Tarek Momen 11-6, 11-8, 8-11, 11-3 in 47 minutes.

Momen had won nine of the pair's previous ten matches on the PSA Tour.

"I don’t have the best record against Tarek," said ElShorbagy.

"The first thing I told him when I won is that ‘I finally beat you!’.

"Every time I lose to him, I go back and try to work something out."

World number one Ali Farag and world number six Mostafa Asal will go head-to-head in an all-Egyptian battle in the other semi-final fixture following respective wins over Frenchman Gregoire Marche and former world number one Karim Abdel Gawad of Egypt.

Farag was troubled after an impressive start from Marche, the only unseeded player to make it this far, but found his feet in the second game to complete a 9-11, 11-6, 11-5, 11-5 triumph.

Asal meanwhile was in fine form to dispatch Gawad 11-6, 11-7, 11-8 in 51 minutes.