No.1 seed Ashleigh Barty extended her winning streak to six with a 6-1, 7-6(7) defeat of Vera Zvonareva in the first round of the US Open in one hour and 28 minutes.

Fresh off the Cincinnati title and seeking her second Grand Slam trophy of the year, Barty was flawless against the 2010 finalist in the first set, but needed to battle hard and save one set point to eke out a knife-edge second.

Zvonareva, bidding for her fifth career win against a reigning World No.1 and first since beating Caroline Wozniacki at the 2011 WTA Finals, did not get going until the tail end of the first set. The Russian, who withdrew ahead of her Cleveland second-round match last week due to a right ankle injury, won just nine points through the first six games to fall behind 1-5, including only three on the Barty serve.

But Zvonareva forced Barty to save two break points before closing out the opener, and then forced the Wimbledon champion to engage in a plethora of bruising baseline exchanges throughout the second. Competing hard, the 36-year-old twice battled back to level from a break down, and it took Barty's finest tennis to get over the line in the tiebreak.

Key stats: Improved serving and a crucial tactical switch saw Zvonareva raise her challenge in the second set. The World No.101 raised her first serve percentage from 65% to 81%, and won six out of eight points at net. Having been almost unable to return the Barty serve in the first set, Zvonareva began to read its direction and decrease the number of cheap points for the Australian.

Barty struck 31 winners to 26 unforced errors in total, and 18 of the latter came in the second set - as did four of her six double faults. Both would loom large in the service games she dropped, while leading 2-1 and when serving for the match at 5-4.

Coming up clutch: Having netted a forehand to miss match point, Barty stared down the barrel of a set point at 6-7 in the tiebreak. Her response was magnificent.

An off forehand winner, bang on the line, got her to 7-7. A delicious touch volley brought up a second match point. And she converted it this time after pummeling from corner to corner through Zvonareva's desperate defences until her opponent finally went long on a backhand.

Words from the winner: "Obviously a tough one against Vera straight up," Barty told the press, after her win. "She's an experienced campaigner. She knows how to get herself into matches. I think all in all, adapting to conditions was a little bit slower than I probably would have liked [but] we're through. We have another chance to improve on that in the next round."

"I think when my back was against the wall late in that buster, I came up with some really good stuff," Barty added. "That's all we can ask is when your back is against the wall, you trust yourself, you go out there and pick your spots and hit them."

What's next for Barty: An intriguing clash with powerful 18-year-old Clara Tauson, who won a contest between former junior World No.1s over Clara Burel 7-5, 6-0 in one hour and 14 minutes.

Both youngsters have surged into the Top 100 this year, with Tauson winning her first WTA trophy in Lyon in March as well as the Chicago 125 two weeks ago, and Burel reaching the Lausanne final in July. World No.78 Tauson has had the upper hand in her rivalry with Burel so far, winning all their previous encounters in juniors and on the ITF World Tour, and that remained the case here.

Burel managed to stick with the Dane through most of the first set, but at 5-6 conceded the set all too easily with a pair of forehand errors and a double fault. The 20-year-old World No.92 continued to fall away throughout a one-sided second set.

Photo by Darren Carroll/USTA

Pliskova, Sakkari assert authority over teenage challengers McNally, Kostyuk

Seeded duo Karolina Pliskova and Maria Sakkari both navigated past talented teenagers with rock-solid straight-sets wins to get their US Open campaigns off to positive starts.

No.4 Pliskova progressed past wildcard Caty McNally 6-3, 6-4 in one hour and 23 minutes to extend her winning streak in major first rounds to 21. A few minutes later, No.17 Sakkari posted a near-identical scoreline, 6-4, 6-3 over Marta Kostyuk in one hour and 31 minutes.

Sakkari's win means that two Greek women have won matches at a Grand Slam for the first time in the Open Era, following compatriot Valentini Grammatikopoulou's defeat of Anna Blinkova on Day 1. Previously, Carol-Ann Kalogeropoulos and Dionissia Asteri both featured in the second round of Roland Garros 1968, though Asteri received a bye to get there.

Key stats: The more experienced players were both able to use formidable serves to dictate the flow of the match. Pliskova and Sakkari each tallied eight aces (and six double faults), and maintained a first serve winning percentage above 70%. By contrast, McNally and Kostyuk landed more of their first deliveries, but won less than half of those points.

Neither were in full control throughout the match. Pliskova raced out to a double break lead in both sets, but was unable to close out a 5-1 lead in the first and found herself pegged back from 3-0 to 3-3 in the second. Sakkari went down a break at the start of the match, and lost an early break lead in the second.

But both found their best serves at the right times to overcome their dips. Sakkari fended off eight out of the 10 break points she faced, frequently with service winners; while Pliskova righted the ship in the second set and hammered down three aces to close out the match.

Youthful inconsistency: McNally and Kostyuk both showcased some wonderfully natural shotmaking - but while their play made for some stellar highlights, neither 19-year-old could find a way to translate it into match momentum.

World No.130 McNally has won four WTA doubles titles since 2019, and this was reflected in several bold net rushes, both serve-and-volleying and coming in off the return. When it paid off, it drew acclaim from the crowd - but Pliskova was often ready for those tactics, and nailed several passes in response.

Kostyuk, perched at a career high of World No.55, also demonstrated her range on the volley and dropshot. But the Ukrainian was too prone to batches of loose errors off the ground, with a slew of errant backhands in the final game encapsulating this.

What's next for Pliskova and Sakkari: Pliskova could face a second young American in a row as Amanda Anisimova celebrates her 20th birthday by taking on Zarina Diyas. Sakkari will meet the in-form Katerina Siniakova, who owns two Top 10 wins this year - over Serena Williams in Parma and Garbiñe Muguruza in Montreal.

Siniakova, who has beaten Sakkari in both of their two most recent meetings, edged former semifinalist Anastasija Sevastova 7-6(6), 6-3, saving one set point in a tense first set along the way.

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