Samantha Stosur and Casey Dellacqua have swept into the second round of the US Open in New York – but fellow Australian Ashleigh Barty is out.

Australia’s only two seeds at the final major of the year, Stosur and Dellacqua both enjoyed straight-sets victories early on day two to join Nick Kyrgios, Matt Ebden and Anastasia Rodionova in advancing.

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Barty, though, was no match for 30th seed Barbora Strycova Zahlavova, falling 6-1 6-3 to the Czech after reaching the main draw with three qualifying wins.

Stosur launched her quest for a second title at Flushing Meadows in imposing fashion, rolling young American Lauren Davis 6-1 6-4 in just 77 minutes on the Grandstand show court.

Intent on avoiding a repeat of her disastrous first-round loss last year to 17-year-old world No.296 Victoria Duval, Stosur was on her game from the get-go.

The 24th seed broke Davis three times to race through the opening set.

She broke the American for a fourth time early in the second before suffering her only service lapse in the fourth game.

Stosur regrouped immediately and, another break and three holds later, booked a second-round meeting on Thursday with Estonian Kaia Kanepi.

“I’m pleased. Look, first rounds can be very tricky,” Stosur said.

“I was certainly prepared for a tough match today, but I was able to come out and play well and do exactly what I wanted to do. So that was a good feeling.”

Stosur made life particularly tough for the 157cm high Davis with her deadly second-serve kicker.

“Tactically, I probably used the right serve at the right time,” she said.

Casey Dellacqua. Photo: Getty

“With the way the conditions were, I was able to use my kick serve a lot and change it up and go hard and able to make her feel uncomfortable on return, which is exactly what I want to do.

“Overall, it was a pretty solid match.”

Seeded for the first time at a grand slam, Dellacqua took only slightly longer to dispatch Austrian Patricia Mayr-Achleitner 7-5 6-3.

Dellacqua next meets Chinese qualifier Qiang Wang after also dropping serve just once in her 85-minute opener.

Five more Australians, including two women, are hoping to progress on Tuesday.

Jarmila Gajdosova meets American Madison Keys, while Croatian-born Ajla Tomljanovic represents Australia for the first time against Spanish 15th seed Carla Suarez Navrarro.

In the men’s event, Marinko Matosevic has a daunting showdown with second seed and five-times champion Roger Federer, Bernard Tomic plays German Dustin Brown and Sam Groth tackles Spaniard Albert Ramos-Vinolas.