Australian Open 2021: AO2021 has entered its 4 day and in the highlight battle of the day, 17 year old Coco Gauff will play 5th seed Elina Svitolina. Rafael Nadal will also play his 2nd round match against the qualifier Michael Mmoh. Some interesting match-ups on Day 4 includes match between Sofia Kenin (4) and Kala Kanepi and 5th seed Stefanos Tsitstipas from Greece vs local lad Thanasi Kokkinakis. Watch the matches Live on Sony Sports.
Sofia Kenin  v Kaia Kanepi: It’s a survival of the fittest. The 22 year-old American, whose serve was broken twice in her first round win over Australian Maddison Inglis, must get past the in-form Estonian to keep her title defense alive. Kanepi, victorious in the pair’s only prior meeting in 2018, is on a hot streak, having sent seeds Aryna Sabalenka, Karolina Muchova and Ekaterina Alexandrova packing en route to the Gippsland Trophy final last week. These wins aren’t one-offs: Kanepi has wins over Simona Halep and Caroline Wozniacki when both sat atop the world rankings, and reached the quarterfinals of the three other majors – but success in Melbourne has so far eluded the powerful 35 year-old.
Stefanos Tsitstipas  v Thanasi Kokkinakis – Who doesn’t love a comeback tale? The talented Aussie, no longer sidelined by injury, broke into tears after snaring his first Australian Open win since 2015. He’s hoping another passion-fueled performance propels him into third round of a major for the first time since Roland Garros that year. Helpfully, Kokkinakis thrives on hardcourts, with one of his career-best wins on the surface over Roger Federer at the 2018 Miami Open. But 22 year-old Tsitsipas, two years his opponent’s junior, enters this match-up as the heavy favourite. The Greek tied Rafael Nadal with 27 wins during the abridged 2020 season, a feat bested by only four others.
Danielle Collins v Karolina Pliskova  : In a rematch of their career-first clash at last week’s Melbourne Summer Series, the agitating American will be looking to hit the repeat button on her straight sets rout of the Czech. 27 year-old Collins is aiming to improve on her semifinal appearance in 2019 and avoid last year’s fate of a second round exit. But the big-serving Pliskova has a breadth of experience and ample weapons with which to exact revenge. Also a 2019 semifinalist at Melbourne Park, the right-hander has won 10 titles on hard courts and remains hungry for a maiden major, having captured the girls’ singles crown here in 2010.
Michael Mmoh (Q) v Rafael Nadal  : Every win this fortnight is a step closer to history for the popular Spaniard, who’s chasing a record 21st major title at AO 2021 — a victory that’d make him the first man in the Open Era to twice win the career Grand Slam. The 23 year-old American qualifier, ranked 177, will rewrite a separate piece of history if he causes an upset because the lowest-ranked player to defeat Nadal here in Melbourne was his countryman Fernando Verdasco, then No. 45, in the first round in 2016. Still, expect Mmoh to win easy points on his serve, which was clocked at 212 kilometers an hour in the first round. That’s quicker than Nadal’s fastest first round serve of 195 kmh.
Coco Gauff v Elina Svitolina  : The American teen sensation has two career top 10 wins: Kiki Bertens in 2019 and Naomi Osaka in 2020. Is a hat trick on the cards in this first-ever match-up? Not if Svitolina has anything to do with it. The deft Ukrainian, who at 26 is a decade older than Gauff, earned her first title since 2018 on the hard courts of Monterrey last year. She’s striving to live up to her seeding by reaching the AO final eight, a journey she made 2018 and 2019 before falling to Elise Mertens and Osaka, respectively.