Defending Davis Cup champions Canada made light of the absence of big names to cruise past Sweden for a second straight victory in the Finals group stage while the United States crashed to their first defeat.

A weakened Canada, already missing Felix Auger-Aliassime and Milos Raonic, were dealt a blow with Denis Shapovalov still not ready for action due to a recent knee issue.

However, Vasek Pospisil got them off to a good start by beating Leo Borg 7-6(5) 5-7 6-2.

Gabriel Diallo, who played a big role in Canada's stunning win over Italy on Wednesday by beating Lorenzo Musetti, helped them take an unassailable 2-0 lead over Sweden in the Group A tie in Bologna as he eased past Elias Ymer 6-4 6-3.

"I'm happy with the way I competed," world number 158 Diallo said. "Obviously things are going my way right now, so it's easy to stay positive.

"I knew that coming into this week rankings didn't really matter in the Davis Cup because there's something about playing for your country that can inspire players... we try to go on court and compete as hard as we can and find a way to win.

Australia jump-started their bid to make the knockout rounds in Malaga in November, as the 2022 runners-up beat France 2-1 in Group B in Manchester.

Max Purcell and Matthew Ebden prevailed 7-5 6-3 in their decisive doubles rubber against Nicolas Mahut and Edouard Roger-Vasselin.

In the Croatian city of Split, the Netherlands handed the United States their first defeat in Group D.

Botic Van de Zandschulp edged a tight opening set against Tommy Paul before dismantling the world number 13 for a 7-6(2) 6-2 victory before Tallon Griekspoor dug deep to beat Frances Tiafoe 6-3 6-7(7) 7-6(3).

It was Tiafoe's second straight defeat this week after the world number 11 had crashed against Croatia's Borna Gojo.

Over in Valencia, the Czech Republic backed up their Group C win over Spain by defeating South Korea, but all eyes will be on Novak Djokovic who could return to action for Serbia when they take on the hosts on Friday.

World number one Djokovic, who won the U.S. Open last week before flying in for Davis Cup duty, defended the decision of Carlos Alcaraz to skip Spain's group ties to recuperate following his semi-final defeat in New York.

"I always protect the players in these situations. Maybe you guys are upset he's not here playing for Spain, because he's 20 and I'm 36 and how he's tired and I'm not," Djokovic said.

"It's important to understand he's got a lot of time ahead of him. You can't forget that he won the U.S. Open last year and after a few days was playing with heart and passion for his country.

"I know he loves to represent Spain and I'm sure he will many times. I'm sure he'll win this competition with Spain because of who he is and the quality he possesses and the quality the team possesses."

(Reporting by Shrivathsa Sridhar in Bengaluru, editing by Pritha Sarkar)