Juan Manuel Cerundolo and Quentin Halys headlined a stunning day of upsets at the Swiss Open 2026 in Gstaad on Friday, 18 July 2026, as all three top seeds — Alexander Bublik, Casper Ruud, and Valentin Vacherot — were eliminated from the ATP 250 clay-court event in a single afternoon. The Swiss mountain venue witnessed one of its most dramatic quarter-final days in recent memory.

Cerundolo Turns the Match Around Against Ruud

Argentine Juan Manuel Cerundolo, ranked No. 45 in the ATP Rankings, produced a remarkable comeback to defeat second seed Casper Ruud 3-6, 7-5, 6-2 in two hours and 15 minutes. Ruud had built a 4-2 lead in the second set and appeared in firm control before Cerundolo reversed the tide.

'I put all my energy into trying to feel my best,' Cerundolo said in his on-court interview. 'He was beating me well. He was doing better and a break up with the wind in his favour. He made maybe two mistakes so that I could come back in the second set. The break point was unbelievable… Then I managed to win the game, and I started playing really well.'

Notably, this is not the first time Cerundolo has upended Ruud in Gstaad — he also defeated the 2021 and 2022 champion in the 2025 quarter-finals, making him the only player to have beaten Ruud at this venue. The result comes weeks after Cerundolo famously rallied from two sets and a double break down to defeat a physically struggling World No. 1 Jannik Sinner at Roland Garros in May, underlining his reputation as one of the tour's most dangerous upset specialists on clay.

Bublik Toppled by Halys in Rain-Delayed Thriller

French qualifier Quentin Halys, ranked World No. 90, completed a rain-interrupted second-round victory over top seed Alexander Bublik — World No. 11 — with a 6-7(4), 6-4, 7-6(5) scoreline. Halys returned to court serving at 5-6 in the deciding set after Thursday's suspension and held firm to seal the upset.

'Coming back at 5-6 in the third set, it was strange, but I think the level was really high from both sides yesterday and even more today,' Halys said. 'I'm so pleased. He is such a good player, and he serves crazy well here with the conditions, so I'm so happy I managed to go through this match.'

According to Infosys ATP Stats, Halys won 92 per cent (46/50) of points behind his first serve against Bublik — a remarkable serving display that proved decisive on the high-altitude Swiss clay.

Halys Exit and Vacherot's Defeat Complete the Chaos

Despite his heroics against Bublik, the 29-year-old Halys could not sustain momentum in the quarter-finals. Aleksandr Shevchenko, who had earlier beaten home favourite Dominic Stricker 7-6(5), 6-2 in another suspended match, defeated Halys 7-6(5), 6-3 to advance to the semi-finals.

Third seed Valentin Vacherot also fell on the day, losing to Belgium's Raphael Collignon 7-6(7), 4-6, 7-5.

Semi-Final Line-Up

The last four at Gstaad 2026 is now set: Cerundolo faces Collignon, while Shevchenko awaits the winner of the fourth seed Arthur Rinderknech versus Stefanos Tsitsipas. With the top three seeds gone, the title is wide open heading into the weekend.