ST. PETERSBURG, Russia — Sixth-seeded Albert Ramos-Vinolas lost in the first round of the St. Petersburg Open in straight sets to French qualifier Alexandre Sidorenko on Tuesday.

The St. Petersburg-born Sidorenko, playing his first tour-level match this year, produced some timely big serves to win 7-5, 6-2 against his Spanish opponent, who at 32nd in the world was ranked 223 places above Sidorenko.

There was a tense finish as Sidorenko wasted two match points, the second with a double fault, before serving out the win.

He next plays Italy’s Paolo Lorenzi, who had to dig deep to beat German qualifier Mischa Zverev 3-6, 7-6 (6), 6-0.