Two former world number one tennis stars, Naomi Osaka and Victoria Azarenka, made it through to the second round of the Bad Homburg Open, a key grass-court warm-up event for Wimbledon, on Monday.

Osaka, the Japanese powerhouse, faced Serbian qualifier Olga Danilovic in a thrilling encounter that stretched just over two hours. Despite a tough challenge, Osaka triumphed 7-6 (8/6), 7-6 (7/4) in a match dominated by big serves. Osaka’s 16 aces outnumbered Danilovic’s 10, but it was the tight tiebreaks that truly made the difference.

“I’m really excited about my first grass-court win of the year,” said Osaka, who received a wildcard entry into the main draw. “I think I have potential on grass, but everyone else is also really good. I can never take it for granted, the wins. Just super excited that I won today.”

The victory ended a three-match losing streak for the four-time Grand Slam champion, who had struggled in Rome, at the French Open, and in Berlin as she continues her return after a maternity break last year. Osaka will now face fifth-seeded Emma Navarro of the United States in the second round.

Osaka saved four break points during the match, while Danilovic fended off six, with both players displaying incredible resilience. In a gripping first-set tiebreak, Osaka fought back from a 4-2 deficit, using her backhand to force an error and securing the first set on her second set point. The second set saw Danilovic starting strong, serving three consecutive aces, but Osaka’s sharp focus and a crucial review of a disputed ace shifted the momentum in her favor.

Meanwhile, Victoria Azarenka, the two-time Australian Open champion, breezed past Germany’s Laura Siegemund with a commanding 6-2, 6-2 victory. Azarenka, 35, had to qualify for this week’s main draw but looked in fine form, sealing the win in just over an hour. The Belarusian will now face Poland’s Iga Swiatek in what promises to be a thrilling second-round match-up.

Also advancing on the day was Croatian Donna Vekic, who reversed last year’s defeat in the Bad Homburg final to Diana Shnaider. Vekic saved all four break points she faced in a 6-3, 6-3 win, setting up a second-round clash with Czech Linda Noskova, who dispatched Australia’s Ajla Tomljanovic 6-3, 6-2.

With the tournament heating up, all eyes will be on the second round as top players such as Osaka and Azarenka continue to battle for supremacy ahead of Wimbledon.