The third-seeded Barthel had three set points at 5-4 in the first set against Heather Watson, but eventually lost it in a tie-break. The Brit was two points from victory in the second set tie-break at 5-4 and 5-5, but Barthel rallied and then rolled in the third set en route to a 67(5) 76(5) 61 triumph that was the longest match of the day at two hours, 38 minutes.
"It was a really tough match. I had some problems getting used to the court," Barthel said. "She was playing really well. But I kept calm, started serving better and not making as many unforced errors, and made things tougher for her."
Second-seeded Belgian Yanina Wickmayer came into this event just 3-7 in her last 10 matches, however, she looked in good form against Alison Riske. From 3-2 in the first set she netted five straight games to clinch the first set and grab the momentum in the second set of her 63 63 win.
"I'm happy about the way I handled her game," Wickmayer said. "I started off a bit slow and made some mistakes. But after that, I picked it up.
"I like to play indoors and I never played this tournament before. My year has been a bit up and down. I wanted to get some more matches in and get some more rhythm, and this is a good tournament for me to do that."
Eighteen-year-old German Annika Beck endured a dramatic second set to secure her first WTA main draw match win, 61 76(11). Up a set and serving for the match at 5-4 against No.5 seed Romina Oprandi, she was broken at love. She again served for it at 6-5 and was broken at 15. In the tie-break, she went up 6-4 but did not close it out until her seventh match point.
A third German also advanced, as Tatjana Malek reeled off four straight games from 3-2 down in the second set of her 76(3) 63 defeat of Alexa Glatch. Malek recorded her first WTA main draw win in almost two years by beating Akgul Amanmuradova two weeks ago in the first round of the US Open.
Among those in action Tuesday are defending champion Barbora Zahlavova Strycova and fan favorite Aleksandra Wozniak. The sixth-seeded Zahlavova Strycova will be seeking to end a six match WTA losing streak when she takes on Marie-Ève Pelletier. The fourth-seeded Wozniak plays Elena Vesnina in the evening session. The Canadian native and resident made her WTA qualifying debut here in 2001 and is a two-time semifinalist.