Petra Kvitova was in sparkling form on her return to action in the Hopman Cup.

Story highlights

Top-seeded Czech Republic defeat Bulgaria in the Hopman Cup in Australia

World number two Petra Kvitova beats Tsvetana Pironkova in straight sets

Tomas Berdych seals Czech victory with success over Grigor Dimitrov

World number one Caroline Wozniaki helps Denmark beat United States

CNN  — 

Top seeds the Czech Republic opened their Hopman Cup campaign with a 2-1 Group A victory over Bulgaria on Monday.

World number two Petra Kvitova set the ball rolling in Perth with a 6-4 6-2 success over Tsvetana Pironkova, ranked 46th in the world.

And men’s number seven Tomas Berdych secured the triumph by defeating Grigor Dimitrov 6-4 6-7 6-3.

Hewitt is beaten on comeback

Kvitova believes she will be under more pressure this year, after a remarkable 2011 which saw her win both Wimbledon and the WTA Tour Championships – as well as leading the Czech Republic to their Fed Cup triumph.

“Every season is different. One year ago I was 34th in the world and now I am world ranked second.” Kvitova told reporters after her victory.

“It is not always easy to play on the court and the first match of the year is always tough, but I played well.”

The Bulgarian pairing earned a consolation by saving three match points to win the dead mixed-doubles rubber 2-6 6-3 11-9.

The later Group A match saw world number one Caroline Woznaicki help Denmark to a 2-1 victory over the United States.

Mardy Fish beat Frederik Nielsen 4-6 7-6 6-4 in the men’s singles, but Wozniacki’s 7-6 6-2 success over Bethanie Mattek-Sands drew the United States level.

However, the Danes secured victory when Wozniacki and Nielsen combined to beat the Americans 7-5 6-3.