Tokyo, Japan -- (Sports Network) - Czech Tomas Berdych dominated Argentine Juan Martin del Potro on the way to winning the title at the $869,000 Japan Open Tennis Championships Sunday.

The ninth-seeded Berdych earned a 6-1, 6-4 victory over his fifth-seeded opponent, dealing del Potro just his second loss in his last 31 matches. That included four straight titles for the Argentine after Wimbledon. Del Potro had been 4-0 lifetime in finals until running into Berdych.

A total of 11 aces from Berdych helped boost the Czech to his fourth career title and the $135,000 top prize.

"If someone had told me before the match [how I would control the play] I wouldn't have believed it because I saw Juan Martin playing his earlier matches and he was in really good shape, playing well," said Berdych. "Today I think he had a little bit of bad luck and I think he ate something wrong and he didn't feel well on the court from the beginning. But I think the second set was getting pretty close and I'm very happy that I finished it the way I did."

Berdych, who toppled American Andy Roddick in the semifinals, won his first event since Halle in 2007. He was also a finalist earlier this year, losing to Tommy Robredo in the Bastad title match in July.

Even though he lost, del Potro will rise in the rankings from 12th to a career-high ninth come Monday.

"It was very tough for me," stated del Potro. "He played unbelievably today, I didn't have chance to do anything. I didn't feel well during the match but I think it was more to do with how well he played. But I had a great tournament anyway, so I'm sad because I lost today but I have to be happy for the week."

Del Potro was trying to become the first player since Dutchman Sjeng Schalken to win each of his first five finals.