Mertens, Rybakina survive in San Jose, Keys upset

Elise Mertens and Elena Rybakina both had to endure difficult three-setters to advance at the Mubadala Silicon Valley Classic on Thursday, but home favorite Madison Keys was knocked out in her opening round match.

Top seed Mertens faced former World No.10 Kristina Mladenovic, and required two hours and 40 minutes to obtain a 6-2 4-6 6-4 victory. Mladenovic had a 3-2 lead in career meetings versus the Belgian, but failed to capitalize on her momentum heading into the final set.

Second seed Elena Rybakina fought back from a set deficit to escape with a 2-6 6-0 6-2 win over unseeded American Claire Liu, improving her career record to 2-0 against the World No. 108.

It was not to be for 2017 champion Madison Keys, who fell in straight sets to China's Zhang Shuai. The World No.51 converted her third match point, sending the third seed packing with a 7-5 7-6(5) victory.

Kazakhstan's Yulia Putintseva survived a thrilling encounter with Australia's Ajla Tomljanovic, battling back from a set down to secure a 3-6 7-5 6-3 win. The eighth seed's mental strength was on display, as she saved 14 of 16 break points before pulling off the victory.