San Francisco Frontiers - Defending Brisbane champion Lehecka wins tough opener

Lehecka, the third seed, saw off his sometime training partner Machac 6-4, 6-7 (5/7), 6-2 in almost two-and-a-half hours on Pat Rafter Arena.

The 24-year-old has won two tournaments in his career, both in Australia.

"The weather and the court conditions here are things that I look forward to," he said. "There's no better place to start the season than here."

It was the Czech pair's first meeting on tour, but Lehecka said he and Machac knew each other well.

"It's never easy -- I've known Tomas since we were kids and we actually practised together before we came here to Brisbane," he said.

"It was a great match -- I think the level was high for a first match of the season for both of us, so I'm super happy for the win."

Lehecka now plays American Sebastian Korda, who beat Monaco's Valentin Vacherot 7-6 (7/1), 6-3.

Alex Michelsen survived a tough battle against Australian qualifier James Duckworth 6-7 (4/7), 7-6 (7/2), 6-3 and will next play fellow American Learner Tien.

In the women's draw, qualifying lucky loser Yulia Putintseva of Kazakhstan beat American Hailey Baptiste 6-2, 6-4 to set up a second-round clash with Ukraine's Marta Kostyuk.

Chinese qualifier Zhang Shuai, 36, turned back the clock when she beat Ashlyn Krueger of the US 6-4, 5-7, 6-4.

She will now face former champion and world number five Elena Rybakina.

T.Rivera--SFF