Latvia’s Jelena Ostapenko ended American Coco Gauff’s run at Melbourne Park with a clinical 7-5 6-3 victory to reach the quarter-finals for the first time.

Ostapenko had the crowd laughing with her answer to a question on whether she trusted the automatic line-calling system in use at Melbourne Park.

“To be honest? No,” the former French Open champion said. “I mean honestly, this live electronic system ... sometimes it feels like it makes mistakes. I look at my team because I know sometimes I’m wrong, but I feel some balls are pretty close.”

Yoshihito Nishioka struggled to understand what was happening as he was being blown off the court by Karen Khachanov on Sunday before the Japanese player found his feet in the third set in a 6-0, 6-0, 7-6 (4) defeat.

“This was a strange match for me. I didn’t know what was going on the first two sets,” he said.

“I had to do something different ... so I started just grinding against him. I almost had it in the third set, but it’s not my day so I couldn’t take it.”

American Sebastian Korda reached the quarter-finals of a Grand Slam for the first time on Sunday after defeating Poland’s Hubert Hurkacz 3-6, 6-3, 6-2, 1-6, 7-6 (7) at the Australian Open.

Korda, who dumped 2021 and 2022 runner-up Daniil Medvedev out in the third round, got off to a shaky start on Rod Laver Arena against 2021 Wimbledon semi-finalist Hurkacz but the 29th seed bounced back to take the second and third sets.

Hurkacz, seeded 10th, grabbed the fourth set and earned two break points at 5-5 in the fifth but Korda kept his calm to escape the trouble before they headed into a tie-breaker.

Korda raced to a 7-3 lead in the tie-breaker after winning six consecutive points but Hurkacz came fighting back to level it at 7-7.

Korda did not panic and closed out the victory with a backhand winner after nearly three and a half hours on court.

“It feels awesome. I was not feeling too much energy towards the fourth and fifth sets but you guys (the crowd) picked up me,” Korda said in his on-court interview.

“I tried to stay as calm as I possibly could ... it was difficult but I am very happy with the way I kind of just stayed down and kept going through. The outcome was great.”

The 22-year-old, who will face Karen Khachanov in the quarter-finals after the Russian knocked out Japan’s Yoshihito Nishioka in straight sets, said he became superstitious in the tie-breaker.

“I got a little superstitious with the towel. The towel got me through it,” he laughed. “Every time I went to the towel I won the point, so I just kept going to it - my new friend.”

Coming up shortly on Rod Laver is Tsitsipas vs Sinner, two of the brightest young talents in the men’s game.

Stefanos Tsitsipas feels like he’s been around for a long time now but he is still only 24 and the world No 4 could have a real shot at winning his first grand slam here in Melbourne, having not yet dropped a set. Tsitsipas has reached the semi-finals three times here, including both of the last two years, and has the chance to go one step further following plenty of big-name exits, including Rafael Nadal and Daniil Medvedev who are both out of this side of the draw.

Standing in his way today is the Italian 21-year-old Jannik Sinner, who has made the quarter-finals of every grand slam already in his young career and has the chance to reach another, where the unseeded young Czech Jiri Lehecka awaits.

Andy Murray reminded himself what grand slam glory nights felt like at the Australian Open and hopes his memorable Melbourne run can be a sign of things to come.

The Scot somehow roused himself following his late-night heroics against Thanasi Kokkinakis to battle for another three hours and 29 minutes on Margaret Court Arena against Roberto Bautista Agut.

But this time there was not to be a happy ending as the metronomic Spaniard withstood a Murray fightback to win 6-1 6-7 (7) 6-3 6-4, ending British singles interest for another year in the third round.

“I feel like I gave everything that I had to this event, so I’m proud of that,” said the Scot, who spent 14 hours and three minutes on court during his three matches.

“That is really, in whatever you’re doing, all you can do. You can’t always control the outcome, you can’t control how well you’re going to play. But I’m also disappointed because I put loads of work into the beginning of this year and was playing well enough to have a really good run.

“I think even tonight, I’m competing against a guy who is 20th in the world, and it’s still very tight considering the circumstances. I’m disappointed because I feel like I could have gone quite a bit further.”

You can watch the Australian Open live on Eurosport in the UK. The action will be broadcast on Eurosport’s TV channels, or fans can tune into Discovery+ to stream the tournament, where an Entertainment & Sport pass is available for either £6.99/month or £59.99/year.

Sky has also announced that starting today, Discovery+ will be available at no extra cost for Sky customers, including for Sky Glass and Sky Stream customers.

If you’re not already a Sky customer, you can get a Sky Stream box, which comes with Sky TV and a Netflix basic plan. The device is currently discounted in Sky’s winter sale (was £26 per month, now £24 per month, Sky.com). This is Sky’s new device, and doesn’t require a satellite dish as it streams Sky directly over wifi.

Meanwhile, ESPN has the rights in the US.

Iga Swiatek admitted the pressure of the world number one tag got to her after crashing out of the Australian Open in the fourth round to Wimbledon champion Elena Rybakina.

The Russian-turned-Kazakh has spoken of her frustration at not being scheduled on the main courts since her success at the All England Club and, on Rod Laver Arena, she produced a big-stage performance to win 6-4 6-4.

Rybakina, who would be in the top 10 had Wimbledon offered ranking points, dropped only six points on her first serve during the match and recovered from 3-0 down against a frustrated Swiatek.

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Sunday was the first time Kazakhstan’s Rybakina appeared on one of the two main showcourts at Melbourne Park during this tournament, with the Russia-born player starting her campaign on an outer court.

The venue mattered little to Rybakina.

“I actually played at Rod Laver against Ash Barty in 2020,” she said. “I played really well. I kind of knew what to expect on these big courts, and I just try to do my best and tried to focus on my serve.

“I really don’t care on which court I play. I try to improve from every match.”

The 22nd seed’s win over Swiatek was achieved in less than 90 minutes and she said one of the keys to victory was being on the front foot right from the start.

“When you play against the number one, I think you have really nothing to lose,” Rybakina added. “I knew that I had to be aggressive from the first ball because she’s a great mover, and she defends really well.

“So I was trying to just attack her from the first ball, and it really worked well.”

Wimbledon champion Elena Rybakina set her sights on taking Iga Swiatek’s world number one ranking after knocking the Pole out of the Australian Open with a 6-4 6-4 victory in the fourth round on Sunday.

Rybakina advanced to the quarter-finals at Melbourne Park for the first time with her win at Rod Laver Arena and will meet Latvia’s Jelena Ostapenko for a place in the last four.

Rybakina said there were still “many things to improve” on but that she was a match for anyone if she could continue her current form.

“If I perform like I did this week and it’s going to be consistently for sure, I will say that I can be number one, I can beat anyone,” the 23-year-old added.

“For now I need to find my consistency also.”

Follow all the latest from the Australian Open.