Top seed Gregory Gaultier stands in the way of Australian Cameron Pilley and his maiden appearance in the World Open squash semi-finals.
Unseeded Pilley continued his fine run in Doha with a 11-7 11-6 12-10 third-round victory over African Alister Walker on Tuesday.
Gaultier was not at his fluent best but came through 10-12 9-5 11-9 11-9 against Omar Mosaad, the disconcertingly tall and domineering Egyptian.
The Frenchman will hope to play better when he meets another tall and difficult opponent in Pilley.
Ramy Ashour, the most spectacular player on the world tour, showed he was back in contention for the World Open title with an exhilarating performance that carried the former No.1 into the quarter-finals.
The twice former world champion from Egypt has not competed since suffering hamstring problems six months ago, yet his fitness was good enough to win a pulsating match full of sharp movement by 9-11 11-6 11-5 11-4 against Miguel Rodriguez, the 12th-seeded Colombian.
Ashour next plays Borja Golan, the sixth-seeded Spaniard who beat rising Egyptian Fares Dessouki 11-8 11-4 6-11 11-5.
Ashour's successor as world champion, Englishman Nick Matthew, had to battle harder than expected against Saurav Ghosal, the 14th seeded Indian, trailing 6-9 in the fourth game of his 11-4 11-5 6-11 11-9 victory.
Matthew next plays Amr Shabana, the 35-year-old four times former world champion, to whom he has lost on the last two occasions and who reached the quarter-finals for the 12th time in a row.
The legendary Egyptian did that by overwhelming Max Lee, the rising Hong Kong player, by 11-6 11-7 11-4 with a wonderfully incisive performance in less than half an hour.
Shabana's compatriot Mohamed El Shorbagy, the world No.1, made it three Egyptians in the last eight with an 11-8 9-11 11-9 11-9 win over Simon Rosner of Germany.
This earned El Shorbagy a meeting with one of two unseeded quarter-finalists, Stephen Coppinger of South Africa, who snatched an 84-minute 12-10 9-11 14-12 8-11 11-8 win over 10th-seeded Egyptian Tarek Momen in the longest match of the day.
