The tennis world got a glimpse of the future with 16-year-old Mirra Andreeva knocking out a favourite in the women's draw.
Australian Alex de Minaur avenged the heartbreak of last year's Davis Cup final loss, while the Australian Open crowd was praised by an American who battled in hostile territory.
Here are five quick hits from day four at Melbourne Park.
1. Sweet revenge is taken as de Minaur now looks forward
Alex de Minaur's unbeaten start to 2024 has continued, with the Australian world number 10 into the third round at Melbourne Park.
His 6-3, 6-0, 6-3 victory over Italian Matteo Arnaldi on Tuesday was impressive, as "the Demon" ripped 23 winners and won 18 points from the 19 times he came to the net.
The win was retribution for de Minaur, who was part of Australia's Davis Cup team who fell to Italy in last year's final.
"It's no secret it was heartbreaking at the end of the year, losing to Italy in the Davis Cup final," he said.
"But I told the boys we're going to be back there, we're going to get another chance and today was a little bit of revenge for Australia and I'm happy to be in the next round."
With the disappointment of the Davis Cup now in the rear view mirror, de Minaur can now turn his focus to a deep run at his home slam.
He has wins over Novak Djokovic, Alexander Zverev, and Taylor Fritz this year and his performance on Tuesday against Arnaldi — ranked 41st in the world — was clinical and decisive and showed he is in the form of his career.
2. American 16th seed hears the Australian crowd in his sleep
Crowd noise and movement has been a major focus from the opening days of this year's Australian Open, but American Ben Shelton doesn't mind.
The men's 16th seed was victorious over Australian Chris O'Connell in four sets on Wednesday, competing with a very boisterous crowd cheering for his opponent.
But Shelton, who made the quarterfinals at Melbourne Park last year, said Australian tennis fans knew how to support their home favourites the proper way.
"It was a tough one today against a guy who definitely had that home crowd support," Shelton said after his win.
"That 'Aussie Aussie Aussie, Oi Oi Oi' chant, I hear it when I sleep at night.
"But I love the way you guys support your guys here in Australia. You guys do it right, so everyone who came out today you guys make the atmosphere at AO special."
Daniil Medvedev was less than impressed with the Melbourne Park faithful in 2022, admonishing the crowd after he defeated Nick Kyrgios.
3. Andreeva puts the tennis world on notice
She has already been further in a major despite only being 16 years old, but Mirra Andreeva made the biggest statement of her young career with a dismantling of Ons Jabeur in the second round.
Her 6-2, 6-0 victory was brutal at times, with world number six Jabeur – a three-time major finalist — restricted to just eight points in the first set.
Jabeur was floored by Andreeva's onslaught, with the Russian teenager breaking serve five times during the match.
Andreeva's talent was recognised by the WTA last year when it awarded her its newcomer of the year gong.
The sky seems to be the limit for Andreeva, whose potential run at Melbourne Park may end up being one of the stories of the tournament.
"I didn't expect that I would play this good [in the first set]," Andreeva said.
"The second set was also not bad. So for me, it was an amazing match. I'm super happy with the level that I showed today on the court."
4. Ultimate sporting move after ball kid's mistake
Mistakes can happen in tennis, particularly when it comes to being a ball kid and the total pressure of having to move fast.
That was never more evident than in yesterday's match between American Aleksandar Kovacevic and Russian Karen Khachanov.
In an an attempt to return serve, Kovacevic's shot looped high and sprayed wide, on a trajectory that was clearly taking the ball out.
Moving on instinct, the ball kid watched as it looped in what felt like slow motion, before making the split second decision to catch the ball rather than letting it bounce. It was an understandable error. Players have blown up in the past at kids not moving quick enough — this kid just moved too quickly.
By the letter of the law, it meant the point had to be replayed, causing a frustrated Khachanov to start arguing with the umpire.
But in the ultimate show of sportsmanship, Kovacevic conceded the point and made sure everyone was saved from frustration or embarrassment.
It was good tennis all round.
5. Which Australians are playing today?
- Casper Ruud (11) vs Max Purcell from 12pm AEDT on Margaret Court Arena
- Grigor Dimitrov (13) vs Thanasi Kokkinakis not before 4pm AEDT on John Cain Arena
- Jeļena Ostapenko (11) vs Ajla Tomljanović not before 7pm AEDT on John Cain Arena
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