Spain’s Carla Suarez Navarro celebrated her 30th birthday in style at the US Open on Monday by beating Russian Maria Sharapova 6-4 6-3 to book her place in the quarter-finals. Sharapova, the 2006 champion, had never lost a night session match in New York prior to her first Grand Slam meeting with Suarez Navarro. “Thank you so much guys,” Suarez Navarro said courtside after being wished happy birthday by the crowd. “It’s the first time I’ve played this year at night. I’m very happy because I played a good match.”

Five-times Grand Slam champion Sharapova paid the price for 38 unforced errors and won less than half of her first serve points while committing eight double faults. “I didn’t take care of the chances that I had,” the Russian told reporters. “By chances, I mean the balls that were a little bit shorter.

“I hesitated to move forward. The balls where I did attack, I made unforced errors, especially on that inside-out forehand today.” With her most potent weapon not firing, Sharapova succumbed in one hour and 31 minutes under the floodlights at the Arthur Ashe Stadium, allowing 30th seed Suarez Navarro to record just her second career victory over the Russian in six attempts.

“Maria is a really good player. I mean, she’s one of the best. I’m happy to beat her tonight,” Suarez Navarro said. “Sometimes on this court, it is easy to (get confused). Well, the crowd, the music, it’s crazy. It’s a really good show, but for the players sometimes it’s tough, especially for me.

“I just tried to be focused. I tried to think about not too much things, just my work, my job. Today it worked.” The Spaniard will meet last year’s runner up Madison Keys in the quarters and knows she will be the underdog against the 14th seeded American.

“It will be a really tough match. She is from the United States so the crowd will probably help her,” Suarez Navarro added. “I need to be aggressive … try to be solid, run and fight. This is the way that I can play really good tennis. I have the character inside, sometimes I have to show more but, well, I’m working on that.”

Japan’s Naomi Osaka reached her first Grand Slam quarter-final by beating Aryna Sabalenka 6-3 2-6 6-4 in a pressure-packed clash of two hard-serving 20-year-old prospects. Osaka, who won the Indian Wells Masters tournament in March, fired nine aces and produced 32 unforced errors, 10 fewer than her Belarussian opponent, in a gusty defensive performance.

Sabalenka, who saved three break points in the final set, flung her racket in dismay after committing a double-fault on match point, handing victory to her 19th-ranked opponent. An emotional Osaka wiped tears from her eyes in an on-court interview, thanking the crowd and saying she would not have forgiven herself had she lost.

“I was just thinking I have to fight for every point; even if I break a leg I should try to get to every ball,” she said. Osaka said Sabalenka’s blistering serve had been a key challenge to overcome toward the end of the match.

“I felt like I had a lot of chances to break her in the third set, then she would serve these really amazing serves. Like a part of me knew it was coming, but at the same time I was always very unprepared,” Osaka said. “I’m just real glad I was able to win in the end.” She next faces Lesia Tsurenko of Ukraine.