Dealing with mono, determined Kvitova blasts into US Open 2nd round

World No. 5 Petra Kvitova got off to an encouraging start at the US Open on Tuesday, capping the tournament's first round with a 6-1, 6-1 evisceration of qualifier Laura Siegemund in a breezy 59 minutes.

Kvitova was in control from start to finish, hitting with pace and margin (she committed just eight unforced errors), dictating point after point from the baseline, and winning an incredible 73 percent of her return points en route to breaking Siegemund six times.

It's been an up-and-down season for Kvitova, to say the least. She's won three titles - including the tour's most recent, in New Haven - and doled out one of just two defeats Serena Williams has suffered, but had disappointing results at the Slams and at Premier tournaments.

She was diagnosed with mononucleosis in August.

"It came as a shock to me but at least I finally knew why I had felt so tired," Kvitova told BBC Sports' Piers Newbery just before the US Open.

"However, it's very challenging to get the right balance between relaxing and working. The doctor told me I'm still able to play matches but I can't work too hard in the preparation."

The two-time Wimbledon champ has been at least as far as the semis at each major save the US Open, where she's bafflingly never made it past the fourth round.

"The courts are not quite as fast as I would like ideally, the humidity and hot weather is not the best for me, and the energy of the place doesn't really suit my personality," she told Newbery, by way of explanation. "I like a kind of quiet place - Wimbledon village for example.

"But on the other hand, I have reached the fourth round twice and I truly believe that one day I can turn around all the bad results here and really do well.

"I will do my best to make it happen this year."

It's early yet, but she couldn't have asked for a better start than she got on Tuesday.