Belinda Bencic, who scored her seventh Top 5 win on Monday against Venus Williams, has been on a rankings rollercoaster over the past two years. Having cracked the Top 10 in February 2016, reaching a career high of No.7, sundry injuries and a spell on the sidelines saw her fall to No.318 in September 2017. But she has put together a 32-4 record since her return to the sport - and is already back up to No.78.
A new face in a Slam semifinal is guaranteed. With the losses of Venus Williams, Sloane Stephens, Ekaterina Makarova and Peng Shuai in Monday's first round, there is no player remaining in the third quarter who has reached that stage at a major, and only one who has reached an Australian Open quarterfinal - Zhang Shuai in 2016. The only other two major quarterfinalists are Elina Svitolina (Roland Garros 2015 and 2017) and Belinda Bencic (US Open 2014).
No.7 seed Jelena Ostapenko faces Chinese No.5 Duan Ying-Ying today. Duan is 0-10 against Top 10 players in her career, having won four sets across those matches (against Madison Keys in Beijing 2016; Agnieszka Radwanska in Shenzhen 2017; and Simona Halep in Eastbourne 2017 and Shenzhen 2018).
No.4 seed Elina Svitolina's second round against Katerina Siniakova is a rematch of their US Open first round last year, their only previous meeting. Svitolina won that 6-0, 6-7(5), 6-3. It's also a battle of two of 2018's strongest servers: coming into the Australian Open, the Ukrainian had hit the second most aces on tour this year (34), while Siniakova was joint third with 31.
This year's ace leader is No.12 seed Julia Goerges with 46. The German is riding a 15-match winning streak stretching back to Moscow last October and has made the fourth round in Melbourne three times (2012, 2013 and 2015) - the only Slam at which she has multiple second week showings. Goerges is 5-0 against her opponent today, Alizé Cornet, and has only lost one set to the Frenchwoman - although that was a bagel set en route to a 0-6, 6-4, 6-0 win in the first round of Dallas in 2011.
Belinda Bencic's opponent today, qualifier Luksika Kumkhum, is something of an Australian Open specialist. This is the third time the Thai has reached the second round - including her sole Top 10 victory, over Petra Kvitova in 2014 - but she is yet to win a main draw match at any other Slam.
There are four Ukrainian women in the second round of the Australian Open - a national Slam record. Three of them are in action today: No.4 seed Elina Svitolina, Kateryna Bondarenko (the only mother in the second round) and 15-year-old qualifier Marta Kostyuk. In the top half of the draw, Lesia Tsurenko also won her opening match.
Marta Kostyuk became the youngest player to qualify for a Slam since Sesil Karatantcheva at the Australian Open in 2005 and then the youngest player to win a round in Melbourne since Martina Hingis in 1996. Today, Kostyuk will face wildcard Olivia Rogowska in a bid to become the first 15-year-old to reach the third round of any Slam since Nicole Vaidisova, who beat Maria Vento-Kabchi and Jelena Kostanic at the 2005 Australian Open before falling to Lindsay Davenport.
Two-time Hobart International champion Elise Mertens is making her belated debut at the Australian Open. Ranked No.127 when she won the Melbourne warm-up in 2017, her title run in Tasmania meant that she was unable to compete in the Australian Open qualifying rounds. This year, as the World No.37 there are no such problems. Mertens' second round against No.23 seed Daria Gavrilova is a rematch of their Hopman Cup encounter two weeks ago, won by the Belgian 2-6, 6-4, 6-2. In tour competition, the two players are tied at 1-1, with Gavrilova taking their Rabat second round last year and Mertens gaining revenge in the first round of Roland Garros.
Elina Svitolina has come into the Australian Open off the back of three consecutive career-best Slam showings: a Roland Garros quarterfinal followed by fourth round appearances at Wimbledon and the US Open. Along with Garbiñe Muguruza, she is the only player remaining in the draw to have reached the second week at the past three majors.
No.19 seed Magdalena Rybarikova's rivalry with Kirsten Flipkens, is the longest-running on show today. It stretches back to 2005, when Flipkens beat the Slovak 6-4, 6-3 in the final of the ITF $25,000 event in Hechingen, Germany; Flipkens also won their most recent encounter, in New Haven qualifying last year 6-2, 6-3. However, Rybarikova leads the overall series 4-3.
No.2 seed Caroline Wozniacki's opponent today is Jana Fett, who has a 100% record against Top 20 opposition in her career - albeit just one match, a 6-4, 6-3 win over Kristina Mladenovic in Tokyo last year.
Two-time Wimbledon champion Petra Kvitova suffered a heartbreaking first-round loss to Andrea Petkovic on Tuesday, falling 10-8 in the final set. Simon Cambers writes for ESPN.com that everything she's gone through in the past two years helps to put it in perspective.
The story of the first day in Melbourne was the tumbling of the American contingent - but today, after Madison Keys won her first match since her US Open final run, she told Sandra Harwitt at USA Today to temper expectations.
ORDER OF PLAY
Find out when and where players are up on the third day in Melbourne.
15-year-old prodigy Marta Kostyuk, ranked No.521, has had a spectacular run through qualifying and into the second round, defeating No.25 seed Peng Shuai in the first round. Catch her practising hard as she bids to keep her Melbourne streak going.