Emma Raducanu's quick learning curve continued at the US Open, as the qualifier doled out an efficient revenge against Zhang Shuai to win 6-2, 6-4 in 1 hour and 22 minutes to advance to the third round.

It was the exact length of time that Zhang had needed to defeat Raducanu 6-3, 6-2 in the first round of San Jose one month ago, a match in which the 18-year-old had been comprehensively outplayed.

Interview: Out of the spotlight, Raducanu engineers career surge in U.S.

But Raducanu had gone on to win 12 of her next 14 matches - a quarterfinal at the Landisville ITF W100, a runner-up showing at the Chicago 125 and her current US Open run out of qualifying. This time, it was the experienced Chinese player on the back foot throughout.

For a set and a half, World No.150 Raducanu dominated almost every aspect of the game. The Briton conceded just five points on serve as she advanced to a 6-2, 4-0 lead. Well-disguised changes of direction down the line enabled her to come out on top of most baseline exchanges - in total, Raducanu would strike 27 winners to 11 unforced errors.

Playing the scoreboard: Raducanu's one-sided lead wasn't just due to the quality of her play, but her refusal to let Zhang gain any sort of momentum until it was too late. Three of the teenager's four breaks of Zhang's serve came after multi-deuce tussles in which the 32-year-old held at least one game point. But Raducanu would doggedly cling on, finding her most accurate returns to deny Zhang each time.

Turning point avoided: With Raducanu holding two points to go up 5-1 in the second set, Zhang belatedly came alive. The World No.49 smacked consecutive winners to bring up her first break point, then found a forehand too hot for Raducanu to handle to break.

Neither could Raducanu convert three break points to move up 5-2 in the next game. Instead, Zhang narrowed the gap to 4-3 thanks to greater intensity in her baseline play. Raducanu still had one break in hand, but momentum seemed to have shifted.

Two service winners, a marvellous forehand angle and a third ace put a stop to that. Raducanu's authoritative love hold for 5-3 put her back in the driver's seat and enabled her to close out the match at the first time of asking two games later.

Youth movement: Raducanu is now the youngest player remaining in the US Open draw following the second-round losses of Coco Gauff and Clara Tauson, and joins fellow 18-year-old Leylah Fernandez in the last 32. She has yet to drop a set - indeed, her 27 games lost in five matches so far mean that Raducanu has conceded an average of only 5.4 games per match.

What's next for Raducanu: A tough test against Sara Sorribes Tormo, who won through to the third round of a major for the first time 6-1, 6-3 over Hsieh Su-Wei in one hour and 18 minutes.

Interview: Why tennis-obsessed Sorribes Tormo could be the toughest out on tour

The Spaniard has enjoyed a stellar 2021 - the result extends her record to 30-15, including a Montreal quarterfinal and Cleveland semifinal ahead of the US Open. Grand Slam success has been the last piece of the puzzle: in 17 previous main draws, Sorribes Tormo had lost in the first round 12 times and in the second on five occasions.

Gracheva reprises Badosa victory in New York

When Varvara Gracheva defeated Paula Badosa 6-4, 7-5 in the second round of last year's US Open, the result barely caused a ripple. Indeed, the Russian World No.102 had arguably been on more of an upwards trajectory at the time than Badosa, then the World No.94.

Much has changed since then - for Badosa, anyway. The Spaniard has been one of 2021's most improved players: a 34-13 season record including a maiden title in Belgrade, semifinals in Lyon, Charleston and Madrid, and quarterfinals at Roland Garros, the Olympic Games and Cincinnati meant that she arrived back in New York as the No.24 seed.

Gracheva, by contrast, had only inched up 20 places to No.82 in 12 months, mostly off the back of her maiden WTA semifinal in Cleveland last week.

What hadn't changed was Gracheva's mastery of the hardcourt matchup. The 21-year-old Russian upset Badosa 6-4, 6-4 in one hour and 14 minutes to reach the third round of a major for the third time. Both sets followed the same pattern: Gracheva raced out to an early break, was pegged back by Badosa midway through, but broke her opponent for the set.

Sakkari victorious over Siniakova in Grand Slam full house rivalry; Bencic, Kontaveit through

No.17 seed Maria Sakkari's rivalry with Katerina Siniakova completed a Grand Slam full set, with the Greek winning 6-4, 6-2 to level the head-to-head at two apiece.

The pair have now played four times, once at each Grand Slam. Siniakova's victories both came in three wildly fluctuating sets, in the first round of the 2018 Australian Open and second round of Roland Garros 2019. When Sakkari wins, the contests are more straightforward: today's result joins her 6-3, 6-4 scoreline in the first round of Wimbledon 2017.

Two other seeds progressing with the minimum of fuss were No.11 Belinda Bencic and No.28 Anett Kontaveit. Olympic gold medallist Bencic dispatched Martina Trevisan 6-3, 6-1 in one hour and 12 minutes; a US Open semifinalist in 2019, her most recent appearance, the Swiss has now reached at least the third round here five times out of six showings.

A clash of players in supreme form saw Kontaveit extend her winning streak to seven by besting Bencic's compatriot Jil Teichmann 6-4, 6-1 in one hour and 10 minutes. Teichmann had delivered a brilliant run to reach the Cincinnati final two weeks ago, but Kontaveit was coming off her second career title in Cleveland last week and tallied 20 winners to only seven unforced errors.

Champion's Reel: How Anett Kontaveit won Cleveland 2021