Daniil Medvedev crashed out of the Halle Open in the second round on Wednesday, succumbing to a 6-3 2-6 7-6 (7-5) defeat to Chinese number one Zhang Zhizhen. (More Tennis News)
Medvedev looked to be on course for the third round at 5-3 up in the decisive tie-break, but Zhang won four successive points to reach the last eight.
Zhang had earlier dropped six straight games from 2-2 in the second set, but he responded to losing an early break in the decider with one of his own to restore parity, then came on strong in the tie-break.
He will face Christopher Eubanks in the next round after the American eliminated defending champion Alexander Bublik with a 7-6 (7-5) 4-6 6-3 victory.
Meanwhile, second seed Alexander Zverev avoided an upset as he saw off a spirited performance from Lorenzo Sonego, winning 6-4 7-6 (7-5) to tee up a meeting with Arthur Fils.
Data Debrief: Zhang breaks new ground
Zhang's victory saw him become the first Chinese player to reach the Halle Open quarter-finals, also representing his second top-five victory after he beat Casper Ruud at last year's US Open.