Novak Djokovic’s Serbia will face Jannik Sinner’s Italy on Saturday in the other semifinal match on the indoor hard court at Martin Carpena arena in Malaga, Spain.
Popyrin edged Virtanen in the first set, saving a set point when trailing 6-5 and forcing a tiebreaker that he clinched when his opponent slapped a forehand long.
Virtanen was Finland’s hero in its upset of defending champion Canada on Tuesday, winning both his singles and doubles matches. But his serve let him down against Popyrin in the second set when his fifth double-fault cost him a break.
“(That was) probably the biggest win of my career so far,” Popyrin said. “To win a match that means so much for us is an honor and something I will never forget.”
De Miñaur converted five of 18 break chances against Ruusuvuori. He ended the match by landing a backhand winner on the sideline.
Lleyton Hewitt’s Australia is seeking a second consecutive final. Australia has the second-most Davis Cup titles, with 28 to 32 for the United States, but its last success came in 2003.