SHANGHAI, Oct. 9 (Xinhua) -- Germany's Alexander Zverev went through a tough challenge from Frenchman Jeremy Chardy at the Shanghai Masters on Wednesday, pulling off a 7-6 (13), 7-6 (3) victory to reach the third round.
The 22-year-old German was 5-3 down in the first tie-break and missed five set points until Chardy wilted with an error at 14-13.
Zverev stumbled in the second set to give Chardy a break at 3-2 but his 32-year-old opponent couldn't serve successfully to tie the match at 5-4, as Zverev broke back to enter a second tie-break.
Zverev raced into a 4-1 lead before securing his third round place in 1 hour 48 minutes.
Zverev, the defending ATP Finals champion, has still not qualified for the November Finals in London with three of eight places remaining.
Greece's Stefanos Tsitsipas kept up his chances of qualifying for London with another hard-fought win, 7-6 (3), 7-6 (3) win over Canadian teen Felix Auger-Aliassime.
Italy's Matteo Berrettini, currently ninth in the rankings, is also in the running after progressing to the third round by defeating Chile's Cristian Garin 6-3, 6-3.
He will face Roberto Bautista-Agut next after the Spaniard dispatched American Reilly Opelka 6-4, 7-5.
Russia's Karen Khachanov advanced with a 6-2, 6-4 win over another American Taylor Fritz, while Fritz's compatriot John Isner progressed in a 7-5, 6-3 win over Frenchman Lucas Pouille.