Australia: Jack Sock and CoCo Vandeweghe gave the United States a perfect start to the 30th edition of the mixed team Hopman Cup event by winning their singles matches in the opening tie against Russia on Saturday in Perth.

World number eight Sock needed three sets to subdue the 45th ranked Karen Khachanov, eventually claiming a 6-4, 1-6, 6-3 win after the Russian rallied to win the second set in just 27 minutes with 10 aces and 18 winners.

Sock, champion at the Paris Masters in November, regained control in the deciding set and sprinted through the final three games, sealing the match with an ace.

Earlier, No.10 Vandeweghe, who made the semifinals of both the Australian and US Open earlier this year, needed 96 minutes to defeat the 15th ranked Anastasia Pavlyuchenkova 6-3, 6-3, breaking the Russian's serve twice in each set.

The Russian team gained some consolation by winning the mixed doubles 3-4(5), 4-1, 4-2 under the FAST4 format in the final match of the tie.

The US has claimed the Hopman Cup a record six times but neither Vendeweghe nor Sock has been in a winning team, with the duo losing to France at the last event.

"I had a lot of chances in the final against France last year, I think I had match point against Richard Gasquet," Sock said after Saturday's match. "We take this tournament very seriously and obviously that one hurt, being so close."

"I'm very fortunate to have the chance to come back and hopefully CoCo and I can go one step better this year."

Later Saturday, Switzerland's Belinda Bencic plays Naomi Osaka of Japan, before world number two Roger Federer faces Yuichi Sugita in his only event before launching his Australian Open title defense on Jan.