<p>World number one Ash Barty was made to sweat for a 6-1 7-6(7) win over Vera Zvonareva and a spot in the second round of the US Open on Tuesday.</p>.<p>The top-seeded Australian came out firing on all cylinders and raced to a 3-0 lead in a rapid-fire opening set that was over in 24 minutes.</p>.<p>But what looked to be a straightforward afternoon for Barty turned tense in a grinding second set which the 36-year-old Zvonareva forced to a tiebreak before falling 9-7.</p>.<p>Barty has won five tournaments this season, including a second career Grand Slam at Wimbledon and her US Open tune-up in Cincinnati.</p>.<p>In between those two victories, however, the 25-year-old threw in a dismal performance when she was booted out of the opening round of the Tokyo Olympics by 48th-ranked Sara Sorribes Tormo.</p>.<p>Zvonareva is a former US Open and Wimbledon runner-up but her best results came more than a decade ago and the injury-ravaged Russian has had spotty performances at Grand Slams ever since, not advancing past the second round of any major since 2014.</p>.<p>She embraced her moment back on Arthur Ashe Stadium court, refusing to wave the white flag after a lopsided opening set.</p>.<p>In the end Barty's all-court game and power proved too much for her, with the Australian laying down 11 aces and firing 31 winners compared to nine by her opponent. </p>
<p>World number one Ash Barty was made to sweat for a 6-1 7-6(7) win over Vera Zvonareva and a spot in the second round of the US Open on Tuesday.</p>.<p>The top-seeded Australian came out firing on all cylinders and raced to a 3-0 lead in a rapid-fire opening set that was over in 24 minutes.</p>.<p>But what looked to be a straightforward afternoon for Barty turned tense in a grinding second set which the 36-year-old Zvonareva forced to a tiebreak before falling 9-7.</p>.<p>Barty has won five tournaments this season, including a second career Grand Slam at Wimbledon and her US Open tune-up in Cincinnati.</p>.<p>In between those two victories, however, the 25-year-old threw in a dismal performance when she was booted out of the opening round of the Tokyo Olympics by 48th-ranked Sara Sorribes Tormo.</p>.<p>Zvonareva is a former US Open and Wimbledon runner-up but her best results came more than a decade ago and the injury-ravaged Russian has had spotty performances at Grand Slams ever since, not advancing past the second round of any major since 2014.</p>.<p>She embraced her moment back on Arthur Ashe Stadium court, refusing to wave the white flag after a lopsided opening set.</p>.<p>In the end Barty's all-court game and power proved too much for her, with the Australian laying down 11 aces and firing 31 winners compared to nine by her opponent. </p>