New York: Croatian fifth seed Marin Cilic crashed out and Canadian teen Denis Shapovalov became the youngest man since 1989 into the US Open last 16 in a wild Friday on which absent six-time champion Serena Williams become a mother.
Cilic, the 2014 US Open champion who had been sidelined since a Wimbledon runner-up showing by an adductor strain, was eliminated by Argentine 29th seed Diego Schwartzman 4-6, 7-5, 7-5, 6-4.
"(The injury) played a quite significant part, and just being injured and not being able to keep that good form," Cilic said. "I was struggling with my shots and my serve was off."
His exit ensured a first-time Slam finalist will come from his draw half, which now lacks a top-10 player. "Everyone is improving," Cilic said. "And you have a lot of youngsters coming up that are playing better."
No one proved that better than Shapovalov, the 18-year-old Israeli-born world number 69 who advanced when Britain's Kyle Edmund retired with a neck injury with the Canadian leading 3-6, 6-3, 6-3, 1-0.
Not since 17-year-old Michael Chang 28 years ago had a younger player cracked the fourth round in New York. And no qualifier had reached the last 16 since Gilles Muller in 2008.
"It's never great to win this way. Hopefully it's nothing too serious," said Shapovalov. "It's very unfortunate but at the same time I'm happy to be in the fourth round."
Shapovalov will play for a quarter-final berth against Spanish 12th seed Pablo Carreno Busta, who ousted French qualifier Nicolas Mahut 6-3, 6-4, 6-3.
The Spaniard, who has not dropped a set, will become the first player to face four qualifiers at a Grand Slam in the Open Era (since 1967).
Schwartzman, who improved to 2-13 against top-10 foes, next meets French 16th seed Lucas Pouille, who defeated Kazakh qualifier Mikhail Kukushkin 2-6, 6-3, 6-4, 6-4.
Baby news from Florida turned heads at the year's final Grand Slam event as Williams, a 23-time Grand Slam champion, gave birth to the child she was pregnant with when she won the Australian Open in January.
Sister Venus Williams, a seven-time Grand Slam champion and new aunt, confirmed reports of the birth before walking onto the court for her third-round match against Greece's 95th-ranked Maria Sakkari.
"Obviously I'm super-excited," US ninth seed Venus said. "Words can't describe it." Venus, the Open's oldest woman at 37, lost to Serena in this year's Australian Open final and to Spain's Garbine Muguruza in the Wimbledon final.
Third-seeded Muguruza needed only 62 minutes to dispatch Slovakian 31st seed Magdalena Rybarikova 6-1, 6-1 to continue her best US Open run and take command of the fight for women's world number one.
She eliminated Venus Williams and already ousted second-ranked Simona Halep from the top spot chase. Only current number one Karolina Pliskova and fourth-seeded Elina Svitolina could deny her reaching the top for the first time.
"I just worry about the next match and the next match and the next match," Muguruza said.
Awaiting Muguruza next is Czech 13th seed Petra Kvitova, who defeated French 18th seed Caroline Garcia 6-0, 6-4.
Kvitova, the 2011 and 2014 Wimbledon champion, enjoyed playing in Arthur Ashe Stadium after needing major left hand surgery following a knife attack by a home intruder last December.
"It means a lot," she said. "After everything which I've been through it's happy moments for me."
Italy's Paolo Lorenzi, 35, became the oldest player in the Open Era to reach a Grand Slam last 16 for the first time by defeating countryman Thomas Fabbiano 6-2, 6-4, 6-4.
The night feature on Ashe pits five-time Grand Slam champion Maria Sharapova against 139th-ranked US teen wildcard Sofia Kenin.
Sharapova, the 2006 US Open winner, has already beaten Halep and Hungary's Timea Babos in her first Grand Slam since serving a 15-month doping ban after testing positive for the blood booster meldonium, at the 2016 Australian Open....