Making her Grand Slam debut and becoming the first-ever athlete from China to play in the wheelchair division at one of tenni’s majors, 30-year-old Zhu Zhenzhen did the unthinkable on Wednesday: She shocked world No.1 and six-time Grand Slam winner Diede de Groot in the tournament’s opening round.

“I was very excited to play the first Grand Slam event in my career, and especially in this tournament,” Zhu told itftennis.com via an interpreter. “I started by learning some unfamiliar conditions in the court and then gradually overcoming it. (I think) it would be my best match so far (in my career).”

It was a splash of a debut for Zhu, who was unranked as recently as four years ago and broke into the top eight last August. She beat the Dutchwoman De Groot, champion here in 2018 and 2019, 6-7(3) 6-3 7-5 in two hours, 36 minutes.

She called out China’s wheelchair sports organising committee for helping her achievement.

“I want to make a breakthrough for Chinese wheelchair tennis,” she said. “Last year is the first time I played 10 stops for the whole season, on the tour, so that I can get enough ranking points to get into a Grand Slam. In the last two years, Chinese players have graduated into the international system – we are improving.”

It was a day of upsets across the wheelchair events, which got underway on Day 10 of the Australian Open.

Like de Groot, Gustavo Fernandez of Argentina, the No.2 seed, engaged in a three-set tussle, only to come out on the losing end: Briton Gordon Reid got the better of Fernandez, 6-3 6-7(3) 6-2 in two hours, 25 minutes.

Reid, however, is more established than Zhu at the major level: The 28-year-old won here in 2016 and followed that up with the inaugural men’s wheelchair singles title at Wimbledon. He was runner-up at Roland-Garros last season, losing in the final to Fernandez.

“I think we always say it, but it’s true: The top eight is very strong. Anybody can beat anybody on the day,” Reid said after the win. “It’s difficult to set yourself apart. I’ve been working hard to create more results like this.”

Reid said he spent much of the last 24 hours in bed, having not been feeling well ahead of the match.

It’s a shocking day one here for both de Groot and Fernandez: They both won three out of four majors in the 2019 season, coming within one tournament of capturing the calendar Grand Slam.

As, too, did Dylan Alcott, the quad wheelchair star from Australia, who won here, Roland-Garros and Wimbledon in 2019, which marked the first time the quad event had been held in either Paris or at the All England Club.

In round-robin play for the quad singles, Alcott beat good friend and doubles partner Heath Davidson 6-2 6-0 in front of a spirited crowd on Court 8 in the late afternoon.

“I feel really good starting the year and I love starting it here,” said the 29-year-old. “There was a great crowd out there — it was epic, it was packed. A lot of kids with disabilities were out there, too. I didn’t have that as a kid. It’s changing my life, but a lot of other people’s lives, too.”

In the other quad round-robin match, Great Britain’s Andy Lapthorne, who beat Alcott for the US Open title in September, edged his doubles partner, David Wagner of the USA, 6-3 7-6(6).

While de Groot’s loss sent shock waves through the women’s singles draw, the higher-ranked player won in each of the other three first-round matches, including Aniek van Koot (who will meet Zhu next), Kgothatso Montjane and Yui Kamiji, the Japanese player who is a six-time major champ.

“It’s really difficult to play against my best friend,” said Kamiji of beating her doubles partner, Jordanne Whiley. “We know each other and how to play. I feel very good. My performance was good today. I’m very happy.”

Kamiji, alongside men’s No.1 seed Shingo Kunieda, are two of the highest-profile athletes from Japan ahead of this summer’s Tokyo Paralympics.

2020 marks the first season that the “Golden Slam” is up for grabs across all wheelchair divisions: Winning all four majors as well as the Paralympic gold. A smile spreads across Kamiji’s face when asked about the Summer Games.

“I’m very excited for Tokyo. We still have a few months… I want to prepare and feel better after each tournament,” said Kamiji, the 2017 winner here. “I want to enjoy that moment. The public is excited for it all. I see commercials, big pictures, all of it.”

She added, laughing: “Sometimes I see myself, too, yes.”

It’s no laughing matter how complete the career of Kunieda, 35, is. The top seed in the men’s event is going for a record-tying 44th Grand Slam title overall (singles and doubles), which would put him on equal footing with Esther Vergeer, the Dutch player considered to be the greatest wheelchair player of all time.

Kunieda was made to work hard in a 6-4 6-4 triumph over Nicolas Peifer of France. He gets Alfie Hewett, the reigning US Open winner, next, who beat another Frenchman, Stephane Houdet in two tight sets.

Reid next plays Joachim Gerard for a spot in the final on the bottom half of the draw.

Though big-time upsets of top seeds are rare in wheelchair tennis, they are not unheard of. Zhu’s win on Wednesday sent murmurs through the locker room and player café, as did Reid’s triumph.

“In the Paralympic world, it’s great to see the Chinese getting behind their athletes,” said Alcott of Zhu. “At one point, these people were told to stay home. It’s her first Grand Slam and she beats the world No.1? Good on her.”

Alcott also is looking forward to the Paralympic season, with the Games set to be held August 25 to September 6. The athletes will go directly from Tokyo to New York, where they will finish the major season at the US Open.

De Groot’s focus here will turn to the doubles, where she is partnered with countrywoman Van Koot. She said a back injury, which altered her off-season training, set her back on Wednesday, though she is no longer in pain.

“She did what she had to do,” de Groot said of Zhu. “Get all the balls back and make it very difficult for me. She played really well. … I put up a good fight, I tried everything. I created some chances for myself but it wasn’t enough. (But) I am glad I tried. I had to give myself that chance. I think it’s good for her to be in the top eight because she can beat us. She makes it tough for us, she has the level.”

As for Zhu, now undefeated at the majors (at 1-0 overall, that is), there is little time to soak in her win: “I can’t be too happy… too relaxed,” she said, then laughing. “I have another tough match to play tomorrow. I will be a little bit happy today.”