Americans win 1st match at Hopman Cup mixed teams event

FILE - In this July 8, 2016, file photo, Roger Federer of Switzerland returns to Milos Raonic of Canada during their men's semifinal singles match at the Wimbledon Tennis Championships in London. Federer will return to competitive tennis at the Hopman Cup tournament in Perth, Australia, starting on Jan. 1, 2017.  (AP Photo/Ben Curtis, File)

PERTH, Australia (AP) Coco Vandeweghe gave the United States an early lead and Jack Sock clinched the Americans’ opening match Sunday at the Hopman Cup mixed teams tournament.

Vandeweghe beat Lucie Hradecka 6-4, 6-2 of Czech Republic before Sock defeated Adam Pavlasek 7-5, 3-6, 6-3 to clinch the match ahead of the mixed doubles, which this year will feature the Fast4 format, including a tiebreaker at 3-3, no advantage and gender-to-gender serving.

Hradecka replaced two-time Wimbledon champion Petra Kvitova after Kvitova was injured 10 days ago in a knife attack by an intruder in her home in the town of Prostejov. Kvitova is expected to be off the tour for up to six months.

”I played a decently clean match, it’s always going to be a little bit interesting your first time out on the court,” Vandeweghe said. ”A little pre-match jitters but I thought I did a good job.”

The United States has won the Hopman Cup a record six times in the tournament’s 28-year history.

Defending champions Australia, represented by Russian-born Daria Gavrilova and Nick Kyrgios, were scheduled to play a late match Sunday against Spain.

Roger Federer, making his return after a six-month left knee injury layoff, and Belinda Bencic begin play for Switzerland against Britain, represented by Heather Wilson and Dan Evans, on Monday night.