Perth - Wimbledon winner Petra Kvitova and partner Tomas Berdych combined to produce a perfect record in Hopman Cup play as the Europeans thrashed the six-time champions United States for an unbeatable 2-0 scoreline on Wednesday.
The top seeds at the mixed team event clinched victory with Berdych's 6-3, 6-3 defeat of Mardy Fish. Kvitova did her part by hammering Bethanie Mattek-Sands 6-2, 6-1.
"These wins were very important," said world No 7 Berdych after beating No 8 Fish, "To win is good for confidence. I'm happy to start the year like this.
"I didn't get much of an off-season, but the fact that my season was long means I'm doing well - that's always the better option.
"This is a solid week but we are not in the final yet, we still have to play well one more time."
Kvitova also maintained an unbeaten record. "I'm happy that I won, but still I have a lot of space for improving.
"I didn't feel very comfortable on the court. It's very good that I won, but still.... every match is really important."
Kvitova stands only a handful of points behind world No 1 Caroline Wozniacki in the WTA race and can overtake the Dane perhaps as early as next week given more winning performances in Sydney.
But Kvitova, as usual, plays down any rivalry. "It's still all preparation at the beginning of the season. You never know how well she can play or what she improved in the off-season.
"So we will see. It will be a nice match for people," she said of the Friday encounter.
Bulgaria threw the group into chaos with a 2-1 victory over Denmark which left both nations with 1-1 records.
Tsvetana Pironkova and Grigor Dimitrov combined in the deciding mixed doubles rubber to insure the winning 2-1 scoreline with a 3-6, 6-4, 10-1 (match tiebreak) result.
Dimitrov, ranked 76th, defeated Frederik Neilsen 7-6 (7-5), 6-2 after Wozniacki got off to an early morning 9:30 start, ending her singles work with a defeat of Tsvetana Pironkova 7-5, 4-6, 6-2 to put Denmark into early command.
Wozniacki said she got better as the day went on in a match which lasted two hours, 25 minutes, longest of this edition.
"It's been pretty tough, getting in (from Thailand) to play straight away" she said. "The most important thing is to win and it doesn't matter how.
"It's tough to play a girl like her (Pironkova) because you don't really get the rhythm, she just hammers the ball. You don't know what to expect.
"It was pretty difficult, but I'm happy that I got the win. I've had quite a few tough matches against her in the past so it's a good one to get under my belt."
Dimitrov and Neilsen spent and hour and three-quarters in their match, with the Bulgarian finally emerging the winner on his third match point with a tenth ace.
Results from the mixed teams Hopman Cup tennis tournament at Perth's Burswood Dome on Wednesday:
Bulgaria bt Denmark 2-1
Women's singles: Caroline Wozniacki (DEN) bt Tsvetana Pironkova (BUL) 7-5, 4-6, 6-2
Men's singles: Grigor Dimitrov (BUL) bt Frederik Nielsen (DEN) 7-6 (7/5), 6-2
Mixed doubles: Pironkova/Dimitrov (BUL) bt Wozniacki/Nielsen (DEN) 3-6, 6-4, 10-1 (match tiebreak)
Czech Republic bt United States 3-0
Women's singles: Petra Kvitova (CZE) bt Bethanie Mattek-Sands (USA) 6-2, 6-1
Men's singles: Tomas Berdych (CZE) bt Mardy Fish (USA) 6-3, 6-3
Mixed doubles: Kvitova/Berdych (CZE) bt Mattek-Sands/Fish (USA) 6-3, 7-5