Karen Khachanov and Anastasia Pavlyuchenkova beat Yuichi Sugita and Naomi Osaka 4-1, 4-0 in a Fast4 mixed doubles decider Thursday to give Russia a 2-1 victory over Japan at the Hopman Cup.

The Russian team took advantage of a number of unforced errors by Sugita and Osaka in the Fast4 format, which includes four-game sets, five-point tiebreakers, no advantage and no let scoring.

In earlier singles matches, Khachanov beat Sugita 6-4, 6-2 after Osaka overcame illness to beat 15th-ranked Pavlyuchenkova 6-4, 3-6, 7-6 (5).

Neither team could have qualified for the final on Saturday from Group B. Later Thursday, the Roger Federer-led Switzerland was playing the United States, with the winner advancing to the final.

After not being able to play at all against the U.S. on Tuesday, Osaka required assistance from a doctor during the second set Thursday but was able to continue to beat the Russian player.

"I just feel like to play like that against someone so well, and not be 100 percent and still win, I should be proud of myself," Osaka said.

Pavlyuchenkova leaves Perth without a singles victory. The 2017 Australian Open quarterfinalist also lost to Switzerland's Belinda Bencic and then CoCo Vandeweghe of the U.S.

Germany, 2-0 in Group A, needs to win its match on Friday against Australia to advance to the final.