German number one Simon Rosner celebrated his career-high world No16 ranking this week by beating top-ranked Spaniard Borja Golan in the quarter-finals of the Abierto Mexicano de Raquetas in Mexico in a victory he described as a "huge win".
The PSA World Tour International 70 championship is the biggest Tour event ever to be held in Mexico - and is being staged in spectacular style on an all-glass court sited in the Plaza de los Martires in Toluca, overlooked by the city's historic cathedral
Golan, ranked two places lower than 24-year-old Rosner, reached the last eight after upsetting third-seeded Egyptian Amr Shabana in the opening round.
But Rosner is enjoying the best form of his life and, for the second time in less than two weeks, beat his European rival 11-7, 5-11, 12-10, 12-10 in 64 minutes.
"Pulled out another win against Borja tonight!" tweeted the Paderborn star (pictured with Golan) later. "Won 3:1 in a really tight match! Really happy to be in the semis! Huge win!"
Rosner's opponent in the semi-finals will be Omar Mosaad after the Egyptian pulled off the night's biggest upset.
The world No11 from Cairo celebrated the first victory over higher-ranked compatriot Karim Darwish for more than two years when he defeated the No2 seed 9-11, 11-9, 11-6, 2-11, 12-10 in 64 minutes.
It will be Rosner and Mosaad's first Tour meeting for more than a year - with the Egyptian holding a 2/0 head-to-head advantage.
Gaultier, the world No3, beat Egypt's Mohamed El Shorbagy for the fourth time in a row - but the unseeded 21-year-old extended his higher-ranked opponent for 76 minutes before going down 7-11, 11-5, 13-11, 11-4.
"Lost to Greg in 4..Had a game ball in the 3rd and could have been 2/1 up!!!" El Shorbagy told his Twitter followers later. "Again getting closer and closer!! Can't wait for Hong Kong now!!"
Londoner Barker took four games to get the better of unseeded Nicolas Mueller, ultimately beating the top-ranked Swiss player on the PSA Tour 11-8, 7-11, 11-3, 11-6 in 50 minutes.
Gaultier has a 9/2 head-to-head lead over Barker - but in their most recent meeting, in the British Open in May, it was the Englishman who prevailed to record one of the best wins of his career.
 Gregory Gaultier (FRA) bt Mohamed El Shorbagy (EGY) 7-11, 11-5, 13-11, 11-4 (76m)
 Peter Barker (ENG) bt Nicolas Mueller (SUI) 11-8, 7-11, 11-3, 11-6 (50m)
Simon Rosner (GER) bt Borja Golan (ESP) 11-7, 5-11, 12-10, 12-10 (64m)
Omar Mosaad (EGY) bt  Karim Darwish (EGY) 9-11, 11-9, 11-6, 2-11, 12-10 (64m)