Raphael Collignon stunned world No 8 Alex De Minaur on Saturday for the biggest win of his career as Belgium took a 2-0 lead over Australia in their Davis Cup second-round qualifier.
The 23-year-old, ranked 91, overcame severe cramping at Ken Rosewall Arena in Sydney to score a 7-5, 3-6, 6-3 upset after a 3hr 12min epic.
Belgium No 1 Zizou Bergs then beat Jordan Thompson 7-6 (7/4), 6-4 in the other singles rubber.
It leaves 28-time champions Australia, who were runners-up in 2022 and 2023 and semifinalists last year, needing to win both reverse singles and the doubles on Sunday.
Collignon was always going to be a tricky proposition for De Minaur after posting a career-best win over world number 12 Casper Ruud at the just-completed US Open en route to the third round.
Beating the Australian was his biggest scalp so far.
"It feels amazing, I thought I wouldn't be able to finish the match because I got cramp so bad at the beginning of the third," said Collignon.
"I tried to go for it, focus on the serve and I don't know how I won.
"I think when you play for your country there is no pain... I am very happy."
Grit. Fight. Courage 🇧🇪
— Davis Cup (@DavisCup) September 13, 2025
Raphael Collignon overcame severe cramp to defeat Alex de Minaur 👏#DavisCup pic.twitter.com/Hep97THaOd
After the Belgian took the first set, De Minaur surged back with 10 consecutive points to take charge of the second and with Collignon doubling over with cramp in the first game of the third set, it appeared the Australian would bank the win.
But Collignon heroically battled on to give his country an unexpected advantage.
"It feels great for the team," said Bergs. "We did a great job today, but we are far from the end."
The Davis Cup finals will be hosted by defending champions Italy in November, with the seven teams that win this weekend's qualifiers joining them.
Germany booked their spot by taking an unbeatable 3-0 advantage over Japan on Saturday, while France, Argentina and Austria are all on the brink after taking 2-0 leads in their second-round qualifiers on Friday.
The United States, record 32-times winners, split the first two singles with the Czech Republic, while Denmark get under way against six-time champions Spain in Marbella later Saturday.