SHENZHEN, China — Alexander Zverev withdrew from the Shenzhen Open on Wednesday, citing fatigue three days after winning his first ATP title in St. Petersburg.

Zverev, at 19 the youngest winner on tour in more than eight years, arrived late from Russia, and the German teen was replaced in the draw by lucky loser Thomas Fabbiano, who went on to beat Japan's Yoshihito Nishioka 3-6, 6-3, 6-4 to complete the first round.

Zverev's older brother, Mischa, defeated another Italian, Fabio Fognini, 7-6 (3), 6-4.

Mischa, a qualifier, served 10 aces and won 79 per cent of his service points to book his first quarterfinal since last year in Valencia, where he also defeated Fognini.

Richard Gasquet brushed aside Australian qualifier Andrew Whittington 6-1, 6-0 in the second round, and will play Mischa Zverev in the quarterfinals.

Second-seeded David Goffin of Belgium received a setback in his bid to qualify for the ATP Finals, when he lost to Malek Jaziri of Tunisia 7-6 (2), 3-6, 6-2. Jaziri made his second quarterfinals in as many weeks.