England's James Willstrop and Nick Matthew each progressed to the quarter-finals of the World Championships with straight games victories on Tuesday.
World number one Willstrop beat India's Saurav Ghosal 11-6 11-7 11-2 and now faces 15th seed Borja Golan of Spain.
Then Matthew, the holder of the title, defeated 13th seeded Tarek Momen 11-8 11-9 13-11.
He will play Amr Shabana, the four-time former world champion from Egypt, in the last eight in Doha.
Matthew fought back from 0-6 down in the second game against Momen, and then won critical video review penalty point decisions when he was 8-6 and 9-7 up in the third.
Earlier Leeds-based Willstrop had shown he was adapting to the demands of an unusually testing cool court by producing a consistently immaculate length, subtle disguises and variations of pace against Ghosal, a regular sparring partner at their shared Yorkshire base.
Apart from a brief spell in the middle of the second game, when Ghosal sneaked into a 6-5 lead, Willstrop controlled the match.
"When you go on court each day with each other and spend a lot of your lives together, it's slightly difficult, but a lot of players have to get used to that - it's part of the togetherness the tour brings," the 29-year-old said afterwards.
"I felt I played really well. There was a lot of stuff going through to the back, but we were both hitting an attacking length, and it was focused and punishing. I feel very good."
His next opponent, Golan, overcame English sixth seed Peter Barker 11-7 4-11 11-3 11-3. Willstrop has faced Golan 10 times and won his last five matches against the Spaniard.
Another Englishmen, the 11th seed Daryl Selby, was beaten 3-1 by fourth seed Karim Darwish, the Egyptian prevailing 11-9 13-11 10-12 11-9.
Guernsey's Chris Simpson also bowed out. France's Gregory Gaultier, the number three seed, beat him 11-7 11-6 11-4.