LONDON, June 24 (Xinhua) -- Petra Kvitova's stellar 2018 season continued in Birmingham on Sunday as the No. 4-seeded Czech overcame Slovakia's Magdalena Rybarikova 4-6, 6-1, 6-2 to defend her title at the Nature Valley Classic tournament.

"I didn't really expect to win here," Kvitova said. "I just played match by match, being very happy to be on the grass and the tennis court. For me, I'm surprised."

The former world No. 2 picked up her WTA-leading fifth title of the year as well as her 37th match victory this season. Kvitova improves to 2-0 against Rybarikova on the WTA, having also defeated the Slovak in the final of the Connecticut Open in 2014.

"I'm already pleased with this part of the season," Kvitova continued. "I couldn't imagine to have five titles this time of the year, so I'm pretty happy already."

"Rybarikova is a tricky player, so it's always time to get used to. She has a little bit different serve as well. I needed a little bit of time to get used to spins and slices and volleys and whatever she plays," she added.