Switzerland's Müller won the opening game, but Farag, last year's runner-up, came out on top to secure a place in the quarter-finals.

The final score, after 77 minutes, was 10-12, 11-8, 11-9, 9-11, 11-7 in the Egyptian's favour, with the match played on a glass court in front of the iconic Great Pyramid of Giza.

He will meet Frenchman Grégory Gaultier in he last eight, after the 39-year-old knocked off Colombia's eighth seed Miguel Rodriguez.

The 2015 world champion, who spent more than a year out after breaking a bone in his knee in late 2018, has not reached the quarter-finals of a Professional Squash Association (PSA) World Tour event since the 2018 US Open, a little more than two years ago.

Farag beat Gaultier in the last eight on that occasion. 

"I’m very happy I kept digging in," Gaultier said.

"Mentally I stayed focused despite it all, and I’m chuffed to get through, they were two tricky matches in a row."

Fourth seed Paul Coll and 19-year-old Mostafa Asal are also through to the last eight.

New Zealand's Coll beat home player Youssef Ibrahim 11-9, 11-4, 12-10.

Asal, also Egyptian, beat England's James Willstrop - the reigning Commonwealth Games champion - 11-5, 11-8, 11-5.

In the women's contest, top seed Nouran Gohar made quick work of fellow Egyptian Rowan Elaraby, triumphing 11-4, 11-9, 11-5.

Nele Gilis of Belgium awaits in the quarter-finals following a 5-11, 11-5, 11-6, 11-5 win over Canadian Hollie Naughton.

French third seed Camille Serme needed to come from behind to beat American Sabrina Sobhy.

However she did, winning 11-6, 12-14, 9-11, 12-10, 11-7 to set up a quarter-final versus Hania El Hammamy.

Egypt's El Hammamy was an 11-9, 11-4, 13-15, 11-9 victor over Belgian Tinne Gilis.

Four men's third-round matches and four women's third-round matches are scheduled tomorrow, with the quarter-finals beginning the following day.

One of the PSA's showpiece events, the Egyptian Open is due to reach its climax on Saturday (October 17).