Serving it up for slam bid

ASHLEIGH Barty’s killer serve has emerged as the greatest second-week danger to Serena Williams’ quest for a seventh US Open crown and record-equalling 24th grand slam title.

Barty is through to the last 16 of a major for the first time – but isn’t done yet.

The 22-year-old former Wimbledon girls’ champion will carry a 2-1 winning record into her fourth-round clash with eighth-seeded 2016 Open runner-up Karolina Pliskova.

“Obviously Karolina’s played well here in New York before. She probably had her first biggest breakthrough here, when she made the final,” Barty said. “She’s got a very big game, a very big game.”

But Barty’s own big game was good enough to see off Pliskova in their only previous meeting on a hard court, in Wuhan last October.

And now Australia’s 18th seed is bringing it in New

York.

Revealing statistics show Barty’s serve to be the second-most effective in the draw, behind only the great Williams.

The Queenslander has faced just eight break points in three matches, two more than Williams, while her 25from-29 service games won is only bettered by the American (23 from 24) and Japanese star Naomi Osaka (21 from 22).

“The whole summer I’ve felt like I’ve served pretty well,” Barty said.

Keeping the points short is also proving key to her progression through the draw.

Barty’s deadly one-two punch has delivered a 50-point advantage over her rivals over the first three rounds when her rallies last four shots or less.