Serena eyeing Last 16 berth in spite of cold shoulder

Serena Williams seems to be making history almost every time she steps on the tennis court as she speeds toward the second week of the US Open in search of a seventh title.

With a victory over Sweden's Johanna Larsson on Saturday, the world number one would notch a 307th career Grand Slam match win, surpassing Martina Navratilova for the most for a woman in the Open Era, and equalling Roger Federer's record total.

“Sometimes I don't even know that I'm hitting these milestones”, Williams said. “This one's kind of cool”.

As she vies for a place in the Round of 16, Williams said her troublesome right shoulder remains a concern, requiring “tons of treatment, tons of rehab, tons of ice. It's constant”.

Nevertheless Williams, who can move past the Open Era record she shares with Steffi Graf if she goes all the way to a 23rd Grand Slam title in New York, will step onto Arthur Ashe Stadium court an overwhelming favorite against the 47th-ranked Larsson, who has never made it past the third round of a Grand Slam.

World number two Andy Murray, vying to become just the fourth man to reach all four Grand Slam finals in a calendar year, is also odds on as he goes up against Italian journeyman Paolo Lorenzi. Lorenzi won his first ATP title at the age of 34 in Kitzbuehel in July. He's in uncharted waters as his two victories so far this week equal his total prior wins at majors over his past 13 years as a pro.

Hungarian Timea Babos put a scare into Romanian fifth seed Simona Halep, surging back in the second set and taking a 3-1 lead in the third before falling 6-1, 2-6, 6-4. “I don't know how I came back”, said Halep, whose unforced errors skyrocketed in the second set. “I was fighting to the very end for every ball”.

Having regained the break to level the third at 3-3, Halep was unable to convert two break points in the eighth game. But Babos, unable to convert two game points in the 10th, finally surrendered with a whimper with a double fault on match point. Halep, who fell in the semi-finals to eventual champion Flavia Pennetta last year, will play Spain's Carla Suárez for place in the quarter-finals.

Suárez celebrated her 28th birthday with a 6-4, 6-3 victory over Russian Elena Vesnina. There was no such drama for fourth seed Agnieszka Radwanska, who needed 70 minutes to defeat France's Caroline García 6-2, 6-3. Sixth seed Venus Williams, whose seven Grand Slam titles include US Open crowns in 2000 and 2001, opens the night session on Ashe against 26th-seeded Laura Siegemund in the first meeting between the two.

Other duels for places in the last 16 see men's third seed Stan Wawrinka, a two-time Grand Slam champion and a two-time semi-finalist in New York, take on 64th-ranked Briton Daniel Evans while sixth-seeded Kei Nishikori, beaten finalist in 2014, plays France's Nicolas Mahut.

Australian Nick Kyrgios closes the show on Ashe against Illya Marchenko - a Ukrainian ranked 47 spots below him who wasn't shy about his goal of upstaging the 14th-seeded firebrand. “I beat Monfils here last year, I beat Ferrer this year. So I know everything can happen and I can play really good and I can beat those guys”, Marchenko said, although he's well aware of the arsenal of “unbelievable shots and unbelievable attacks” the immensely talented but mercurial Kyrgios can unleash.