A year after he knocked out the then world No.6 Andrey Rublev at Monaco's prestigious Country Club, the beanpole Australian this time accounted for No.7-ranked Ruud 6-4 3-6 7-5 at his most successful European clay-court venue on Thursday in a draining, near three-hour tussle.
Twice, the Sydneysider was a point away from defeat when 5-3 down in the deciding set before he rallied to go on the attack against Norway's three-time grand slam finalist and reel off the final four games for one of the best clay-court triumphs of his career.
It also put a dreadful start to his year behind Popyrin, who had only won two matches before turning up in the Principality for his first outing of the clay-court season.
"No, I'm 3 and 0 this year -- I'm forgetting about the start of the year for me!" laughed the 25-year-old Popyrin, when asked about his dismal opening to 2025 after such an impressive breakthrough campaign the previous year.
"It was a tough start of the year but this week is a new week, and the year is really, really long, and I just have to put in the work and forget about the last couple of months -- and that's what I've done this week."Â
The two-hour 56-minute win over Ruud, sealed by a cross-court volley which was his 49th winner of the match, set Popyrin up with a quarter-final date on Friday against Spain's Alejandro Davidovich Fokina.
Davidovich Fokina had earlier also pulled off a shock by defeating in-form British fifth seed Jack Draper 6-3 6-7 (6-8) 6-4.
