TENNIS: World No.2 Roger Federer continued his strong early-season form with a 6-3 7-6 (10-8) win over Russian Karen Khachanov at the Hopman Cup on Tuesday night.
Federer was broken in his first service game, but bounced back strongly to win the match in 77 minutes and give Switzerland a 1-0 lead in the tie.
Former world No.7 Belinda Bencic then made it 2-0 with a tough 6-1 3-6 6-3 win over Anastasia Pavlyuchenkova in the women's singles rubber.
Federer and Bencic then teamed up to win Pavlyuchenkova and Khachanov 4-3 (1) 3-4 (3) 4-1 in the fast4 doubles tie.
Federer started his Hopman Cup campaign with a straight sets win over Japan's Yuichi Sugita.
And although he started slowly against Khachanov, he quickly bounced back to win the opening set in 29 minutes.
The second set was an entertaining arm wrestle as both players produced powerful service games.
But Federer finally cracked the Russian in an epic tiebreak, saving a set point to secure the win on his third match point, courtesy of a successful challenge.
Meanwhile, Hopman Cup director Paul Kilderry has a contingency plan in place should American Jack Sock not recover from his hip injury in time to face Federer on Thursday night.
Sock retired early in the second set of his clash with Japan's Yuichi Sugita on Tuesday morning, but the world No.8 is expected to be fit for their sellout tie against Switzerland.
The winner of the tie is likely to claim Group B and win through to the final of the mixed-teams tournament in Perth.
The team of Sock and CoCo Vandeweghe are chasing the US's seventh Hopman Cup title.
If Federer and Belinda Bencic are successful, it will be Switzerland's third tournament championship.
After losing the opening set, Sock received treatment for an injured hip he received after he took a fall earlier in the set.
He tried to continue but retired early in the second set with the scores at 7-6(1) 1-1.
Kilderry expected Sock to bounce back but had a back-up plan, just in case.
"I just spoke to Jack and he feels like he'll be fine," Kilderry said.
"He has had some treatment on it and feels like he'll be good to go. He said it felt uncomfortable out there, so I think he was just a little nervous doing more damage.
"Thursday night is a sellout. We'll certainly have something in place if he wasn't to feel great, but... he's very confident he'll be fine. He's had it before and he knows what he's dealing with."
Pat Cash, who is coaching Vandeweghe, took Sock's place in an exhibition fast4 mixed doubles match.
Cash is not a part of the contingency plan for Thursday night, nor is the tournament's back-up male player Blake Ellis.
Japan's Naomi Osaka is also expected to recover in time for Japan's next tie, against Russia, on Thursday.
Osaka did not make it to the court on Tuesday, having fallen ill on Monday night. She forfeited both the singles and the mixed doubles, automatically gifting the US both rubbers.
Osaka was replaced in her singles match against Vandeweghe by 19-year-old Perth local Maddison Inglis, who has been the hitting partner for the American this week.
Vandeweghe survived some anxious moments in the match before winning 7-5 6-2.