Japan Open 2023 Results Today: Shintaro Mochizuki stuns defending champion Taylor Fritz, Alex de Minaur sails into the QF | Day 4

Shintaro Mochizuki made headlines on Day 4 of the 2023 Japan Open with his stunning upset win over defending champion Taylor Fritz.

The 20-year-old from Japan, ranked 215th, had never won a match on the ATP tour prior to this week. Mochizuki has now scored one of the biggest wins of his career by ousting Fritz.

Top players haven't performed too well in Tokyo so far. Earlier in the week, World No. 8 Casper Ruud and last week's Shanghai Masters champion Hubert Hurkacz were also sent packing.

Alex de Minaur and Alexei Popyrin were among the victors on Thursday and joined Mochizuki in the quarterfinals. Here's a recap on how it all went down on Day 4 of the Japan Open:

---

Shintaro Mochizuki stages an epic comeback to end Taylor Fritz's title defense

Taylor Fritz was the defending champion at the Japan Open.

Having lost in the third round in Shanghai last week, Fritz arrived in Tokyo with an aim to better his previous performance. He captured the first set against Mochizuki with ease, not dropping a single game.

The two were on even terms in the second set, but Mochzuki edged out the American to take the set. Fritz got back on track as he pulled ahead 5-2 in the third set. The home favorite then fought back to level the score and take the match into a tie-break.

Mochizuki dictated the terms of the tie-break right from the start and came out on top to complete an impressive comeback. He now finds himself in his maiden quarterfinal on the ATP tour.

As for Fritz, the loss puts a dampener on his ATP Finals chances.

---

Alex de Minaur tops Diego Schwartzman to make the last eight

De Minaur defeated Diego Schwartzman 6-0, 7-5 to sail in the quarterfinals of the Japan Open. He became the first Australian player since Lleyton Hewitt in 2004 to reach at least 10 quarterfinals in a single season.

It has been a career best season for De Minaur so far. He won the biggest title of his career in Acapulco at the start of the year. He also reached three more finals and a career-high ranking of No. 11.

While De Minaur is a fair few points behind the players fighting for a spot in the ATP Finals, a title here would help him close the gap. It would also take him another step closer to cracking the top 10 of the ATP rankings.

---

Alexei Popyrin survives a tough test from Cristian Garin

Alexei Popyrin will be aiming to reach his second semifinal of the year at the Japan Open.

Popyrin staged an inspired fightback to beat Garin 4-6, 7-6 (3), 6-2 in the second round of the Japan Open. After dropping the first set, the Australian trailed 4-2 in the second set. He turned the tables on his opponent to capture the set and take the contest into a decider.

Popyrin was the better player in the third set and faced little resistance from Garin towards the end of the match. He has now made it to his fourth quarterfinal of the season.

Popyrin has advanced beyond this stage just once, which was during his title winning run at the Croatia Open. He will face Mochizuki for a spot in the semifinals.

---

Aslan Karatsev cruises past Zhizhen Zhang

Karatsev continued his impressive run at the Japan Open with a 6-3, 6-4 win over Zhang in the second round. The Russian didn't face a single break point throughout the match.

Karatsev had earlier knocked out sixth seed Frances Tiafoe in straight sets in the first round. He started the Asian swing on a strong note by reaching the semifinals in Zhuhai. However, he crashed out in the first round of the Shanghai Masters.

Karatsev has now bounced back to make the last eight here. He'll next take on fourth seed de Minaur in the quarterfinals.

---

Japan Open 2023: Day 4 results at a glance

Men's singles

(WC) Shintaro Mochizuki def. (1) Taylor Fritz: 0-6, 6-4, 7-6 (2)

(4) Alex de Minaur def. Diego Schwartzman: 6-0, 7-5

Alexei Popyrin def. (Q) Cristian Garin: 4-6, 7-6 (3), 6-2

Aslan Karatsev def. Zhizhen Zhang: 6-3, 6-4

Men's doubles

(3) Jean-Julien Rojer/Marcelo Aravelo def. Yoshihito Nishioka/Ben McLachlan: 6-3, 7-6 (3)

Jamie Murray/Michael Venus def. (4) Sander Gille/Joran Vliegen: 4-6, 7-5, 10-5

Max Purcell/Rinky Hijikata def. Yusuke Watanuki/Sho Shimabukuro: 7-6 (6), 6-4

Jackson Withrow/Nathaniel Lammons def. Kaichi Uchida/Yasutaka Uchiyama: 6-3, 6-4