CoCo Vandeweghe's seismic serve has helped her charge into the WTA Elite Trophy Zhuhai semifinals.

Vandeweghe cites two unlikely sources—frugality and manufactured malice—for fueling her final four run.

Watch: Barty, Vandeweghe Into Zhuhai Semifinals

Following her straight-sets win over Elena Vesnina today, Vandeweghe told the media she's comfortable with the tournament's Yonex balls because she practices with the same balls—free of charge thanks to her racquet sponsor.

"I’m actually pretty used to these balls," Vandeweghe said. "Yonex gives me a case of these balls all the time so I practice with them at home because I’m into free stuff and I’m cheap.

"It’s a combination of that and Yonex treats me well so they give me a free case of balls all the time."



The 12th-ranked American said manufactured rancor helped raise her intensity to scrape out a three-set win over Chinese wild card Peng Shuai in her Zhuhai opener.

“It’s a little bit different each match," Vandeweghe said of her motivational sources. "I think the first match I just made myself hate my opponent so much. That’s pretty much all it was.

"You know, nothing against her, but it was like that was the only way I could get any sort anger and intensity out was that I was gonna hate my opponent that much to get some fire going.

"The second match it was more inward. Just kind of allowing momentum to slip knowing I’ve been talking with (coach) Pat (Cash) a bunch and he’s been very intense with me that I work too darn hard to let these matches slip. So that’s what I was kind of tapping into in today’s match."

Photo credit: WTA Elite Trophy Zhuhai