Berlin - US Olympian Varvara Lepchenko upset South African eighth seed Chanelle Scheepers 6-4, 6-2 on Wednesday to reach her third quarter-final of the season at the WTA hardcourt event.
The 44th-ranked Lepchenko, who will join Venus and Serena Williams plus fellow Carlsbad competitor Christina McHale on the flight to London next week for the July 28 start of the Olympic tennis event, never faced a break point in a victory that took less than 90 minutes.
Lepchenko reached quarter-finals this season indoors in Memphis in February and on the blue clay of May's Madrid Masters, where she lost to Agnieszka Radwanska.
The American broke Scheepers three times and advanced as the South African sailed a return long.
Lepchenko next plays either fourth seed Nadia Petrova of Russia or American Alexa Glatch.
Taiwanese qualifier Chan Yung-Jan beat Britain's Heather Watson 6-3, 7-6 (7/2).
Chan, ranked 161st, will face a Friday test against either fourth seed Jelena Jankovic, the former world No 1 Serb, or Hungarian Melinda Czink.
Chan won the opening set in 40 minutes, breaking Watson in the final game as the British player, who failed to convert on any of her seven break points, served to stay in it.
In the second, six service breaks came thick and fast as the set went to a tiebreaker. Chan took a 5-2 lead and put away a crosscourt volley to earn the victory.
"Today was a difficult match because both of us are pretty solid," Chan said. "The weather was pretty warm today, so it was difficult physically."
French top seed Marion Bartoli was opening her campaign after a first-round bye as she faced American Vania King in the second round.