Maria Sharapova saw her perfect record under the lights of Arthur Ashe Stadium come to an end as she was beaten in straight sets by birthday girl Carla Suarez Navarro in the last 16 of the US Open.

Sharapova - the champion at Flushing Meadows back in 2006 - had won all 22 of her night matches on Ashe prior to Monday.

However, the Russian delivered an error-strewn performance, including eight double faults, as she was beaten 6-4 6-3 by Suarez Navarro on the 30th seed's 30th birthday.

There were also wins for 2017 runner-up Madison Keys, rising star Naomi Osaka and the unseeded Lesia Tsurenko as the quarter-final line-up was completed.

MARIA'S STREAK IS OVA

Despite holding a lower ranking than her opponent, Sharapova undoubtedly started as the favourite for the last-16 tie given her pedigree and immense record in night matches at this venue.

However, the Russian struggled badly with her serve in the opening set, which Suarez Navarro won at the second attempt after being broken with a 5-2 lead.

Both players lifted their level in set two, Suarez Navarro winning a couple of hugely entertaining points that drew loud applause from the crowd.

Yet serving issues continued to blight Sharapova as Suarez Navarro - who possesses the most delightful one-handed backhand - triumphed in straight sets for the first time in the tournament.

KEYS HAPPY TO STAY UNDER THE RADAR

With so much attention naturally focused on Serena Williams and defending champion Sloane Stephens, last year's runner-up, Keys, has been able to make relatively quiet progress into the last eight.

Keys was a comfortable winner over Dominika Cibulkova on Monday, triumphing 6-1 6-3 to record a fifth victory in as many meetings with the Slovakian.

"It's kind of nice to be under the radar," said the 14th seed, who will now face Suarez Navarro.

"I'm pretty used to it either way. This one just seems like it's a little bit more low key."

OSAKA DREAMING OF SERENA SHOWDOWN

Osaka is through to a grand slam quarter-final for the first time, after battling past fellow in-form 20-year-old Aryna Sabalenka in a fascinating encounter on Louis Armstrong Stadium.

The Japanese won an astonishing 22 games in a row on her way to the round of 16, but had to show character to come from a break down in the decider against Sabalenka.

Next up for Osaka is a last-eight meeting with the unseeded Tsurenko, but she is dreaming of a final against her hero.

"It's no secret that Serena is my favourite," she said. "I've watched all of her matches in the US Open this year. I'm just really grateful that she's playing again. I'm grateful that I got the opportunity to play her [and beat her] in Miami [earlier this year].

"I hope I can play her here. That would kind of mean we have to meet in the final."

THIRD TIME LUCKY AS TSURENKO DEFIES HEAT STRUGGLES

In her third appearance in the fourth round of a slam, Tsurenko claimed her first victory.

The Ukrainian and 19-year-old Marketa Vondrousova endured arguably the toughest conditions of the day, playing on the exposed Grandstand court in the middle of the afternoon as temperatures reached 90 degrees.

Tsurenko was clearly struggling as she left the court after losing a first-set tie-break, but nevertheless bounced back to triumph 6-7 (3-7) 7-5 6-2.

"I think it was some type of heat illness or something like that," Tsurenko told reporters after claiming victory.

"I have to say that I've never felt so bad on court. This was something new for me. I usually handle any kind of weather without any problem. But today was one of the toughest matches in my life."