HIROSHIMA, Japan - Qualifier Amanda Anisimova has stunned No.7 seed Zheng Saisai 6-1, 6-1 at the Hana-Cupid Japan Women's Open, storming into her maiden quarterfinal with a near-flawless display of tennis in just one hour and one minute.

"I thought I played really well," the teenager said afterwards. "I was playing a really good player, so I was just preparing myself well mentally - I was just going out there without pressure and trying to have fun."

The American, who turned 17 two weeks ago, is playing only her second WTA-level event outside the USA following her Grand Slam debut, via wildcard, at Roland Garros last year. Her sole other professional appearance outside her home country was in an ITF $25,000 event in Curitiba, Brazil last March, where she reached the final before losing to Anastasia Potapova.

The change of scenery has not fazed Anisimova this week, though. Having come through qualifying for the loss of just one set, to Urszula Radwanska in the second round, the former junior World No.2 has been dominant in the main draw, ploughing into the last eight for the loss of just four games. Today, she backed up her 6-1, 6-1 defeat of Jana Fett in the first round with an identically emphatic scoreline over a seeded opponent, winning 51 points to just 27 for Zheng.

Through the first four games, Anisimova was the only player to hold serve, but an exchange of breaks left the youngster 3-1 up when a rain shower delayed play. On resumption, the World No.134 took control, sending down booming service winners to hold for 4-1 and coming forward to put away a confident drive volley en route to breaking her Chinese opponent for a third time. Another drive volley would seal the set on her third set point a game later.

Anisimova would continue to dazzle with her clean hitting and cool shot selection throughout a 28-minute second set. An inside-out backhand winner was followed by a neat pass to capture the first break, and coming forward continued to pay dividends in negating Zheng's variety and defence. Indeed, Anisimova was impeccable on the drive volley throughout, racking up another three as she reeled off eight consecutive games to leap out to a 4-0 lead.

The Nanchang runner-up continued trying to deploy her courtcraft where she could, with a canny forehand slice and solid serving leading to her first hold of the match, but Anisimova was unstoppable. After dropping serve in the third game of the match, the second-youngest player in the Top 200 would concede only seven further points behind her delivery. As Zheng served to stay in the match, Anisimova even displayed some variety of her own, taking the first point with a dropshot.

Even another inconvenient rain shower on the 17-year-old's second match point couldn't halt her for long: on resumption, Anisimova would seal the win straight away as Zheng shanked a forehand into the sky.

Anisimova, who became the youngest player to hold a Top 10 victory in March when she upset Petra Kvitova en route to the fourth round in Indian Wells, has now compiled a remarkable 22-6 record in 2018 - 9-4 in WTA main draws - despite being sidelined for four months with an ankle injury between March and July, forcing her to miss the clay and grass swings. Musing on the reasons for her success, Anisimova said: "I play really aggressive and that helps me a lot - but also in my off-season, every season I work really hard, and when I do that it prepares me a lot for these big tournaments.

"Also, I played the qualifying here and that gave me a lot of confidence coming into the main draw."

Since her return in San Jose, Anisimova has picked up where she left off - and will have the chance to make a first semifinal against either Anna Karolina Schmiedlova or Viktorija Golubic next. The 2017 US Open junior champion is looking forward to her first taste of the Asian WTA swing: "Here in Asia, I'm going to try to play some back-to-backs, so it's going to be a new experience playing lots of tournaments in a row - and I'm really excited," she enthused.