Naomi Osaka secured her first grass-court victory of the season after beating Olga Danilovic in two tie-break sets in her opening match at the Bad Homburg Open.
Osaka, who had lost her last three matches, was able to get over the line in a hard-fought 7-6 (8-6) 7-6 (7-4) win in just over two hours on Monday.
The former world number one had been given a wildcard for the tournament in Germany, but was unable to break through Danilovic in the opening exchanges.
Osaka was forced to save three break points across two games midway through the opening set, but was able to take the early advantage in the tie-break.
The Japanese looked more comfortable in the second, but struggled to make her advantage count as she missed five break points in the fifth and ninth games.
But Osaka remained composed as the second set went to another tie-break, with the 27-year-old sealing her progression after Danilovic skewed a backhand wide of the mark.
Osaka's reward for her victory is a tough test against fifth seed Emma Navarro in the next round.
Data Debrief: Osaka thrives on serve
In a tightly-contested game that saw neither player broken, Osaka's excellence on serve proved to be the difference in this gripping first-round encounter.
Osaka leads the WTA in percentage of first-serve points won, and fired 16 aces against Danilovic, while only having one double fault to her opponents seven.
But her attentions now turn to Navarro, with the American winning their only previous meeting, which was also on grass, at Wimbledon last year.
