No.1 seed Simona Halep, one of four Romanians to make the second round out of eight in the main draw, takes on Zheng Saisai, the only Chinese player to win a match out of the five competing in the first round. Zheng's career record against Top 10 players is 4-4, but the 24-year-old's only previous encounter with Halep was a loss - 6-2, 6-3 in the 2015 Shenzhen semifinals.

Reigning junior champion Claire Liu is the youngest player in the main draw, and as the World No.237 the lowest-ranked remaining competitor. The 18-year-old faces No.11 seed Angelique Kerber today; the last time the German lost to a player ranked outside the Top 200 was also against a former junior champion at Wimbledon - her 4-6, 7-6(4), 6-3 first-round exit to No.254 Laura Robson here in 2011.

All six former junior champions left in the draw are in action today - and four of them play each other. 2003 girls' winner Kirsten Flipkens takes on 2014 victor Jelena Ostapenko; the Belgian owns both a 9-1 grass record this year, including the 's-Hertogenbosch final and the Southsea ITF $100,000 title, and a 3-0 record against her younger rival. All three of those matches took place in 2015 on hard courts: a three-set win in Fed Cup zonal play followed by a 6-2, 6-0 scoreline in Istanbul and a 6-3, 6-0 victory in the Vancouver ITF $100,000 event.

The other match-up between former junior winners pairs Ashleigh Barty (2011) and Eugenie Bouchard (2012). Despite winning the girls' title first, Barty is two years younger than Bouchard - and the No.17 seed also defeated the Canadian 6-4, 5-7, 6-3 in their only previous encounter, in the first round of Miami last year. However, Bouchard has had greater main draw success here to date, reaching the final in 2014 - whereas Barty's win over Stefanie Voegele on Tuesday was her first main draw match victory at the third attempt.

2003 Wimbledon junior champion Kirsten Flipkens (Getty)

Defending champion Garbiñe Muguruza has played Alison Van Uytvanck once before, winning 6-2, 6-7(1) 6-3 in the 2014 Florianopolis quarterfinals. The Belgian is yet to score a Top 10 win in six previous attempts - although both of her matches against Top 10 players on grass went the distance, a 3-6, 6-3, 8-6 loss to Dominika Cibulkova at Wimbledon in 2014 and a 6-2, 4-6, 7-6(3) defeat by Belinda Bencic in 's-Hertogenbosch in 2016.

No.15 seed Elise Mertens has a 2-1 record against Sachia Vickery - with both victories coming in the same tournament. In Hobart in 2017, she would defeat Vickery 6-4, 6-2 to qualify for the main draw - and again in the second round, when Vickery, who had also made the draw as a lucky loser, retired injured after winning the first game. That result forced Mertens to miss the Australian Open qualifying rounds that year - but it would be a career-changing week for the Belgian anyway, as she went on to win her first title and crack the Top 100 for the first time.

No.27 seed Carla Suárez Navarro's match against Sara Sorribes Tormo is the first all-Spanish encounter at Wimbledon since 2013, when Suárez Navarro defeated Lourdes Domínguez Lino 6-2, 6-2 in the first round. The six-time Grand Slam quarterfinalist has also won both of her matches against Sorribes Tormo, in Linz in 2016 and in Monterrey last year, conceding just seven games in total; Sorribes Tormo's first-round defeat of Kaia Kanepi was the 21-year-old's first major match win at the sixth attempt.

From teammates to opponents: Daria Gavrilova and Samantha Stosur, who play each other today, confer during their first-round loss to Timea Bacsinszky and Martina Hingis at the 2016 Rio Olympic Games (Getty)

No.26 seed Daria Gavrilova faces Samantha Stosur in the first all-Australian match at Wimbledon since Nicole Pratt's first-round defeat of Casey Dellacqua in 2007. It is the sixth time Gavrilova and Stosur have played overall and the fourth this season alone; the 2011 US Open champion leads the overall head-to-head 3-2, including the most recent two matches in Prague (via retirement) and Strasbourg during the clay swing. They have never played on grass before.

Grass-loving Alison Riske is in form on the lawns again this year, having compiled a 12-2 record over the past month including the Surbiton ITF $100,000 title and quarterfinals in 's-Hertogenbosch and Mallorca. The American is 1-1 against 2013 junior champion Belinda Bencic, having won 6-3, 6-4 in the 2014 Tianjin final but lost 6-4, 6-3 in the first round of the 2016 Australian Open.

Seven players will seek to make the third round of a Grand Slam for the first time today: Zheng Saisai, Lara Arruabarrena, Sachia Vickery, Vitalia Diatchenko, Claire Liu, Katie Boulter and Sara Sorribes Tormo. Arruabarrena has fallen in the second round on eight previous occasions - the only active player with a worse record at this stage is Urszula Radwanska, who is 0-9 in second rounds at majors. Diatchenko, who made her Grand Slam debut at Roland Garros in 2009, won just her third main draw match in a major on Tuesday to upset No.24 seed Maria Sharapova.

Home favorite Johanna Konta has a 2-1 record over former Australian Open finalist Dominika Cibulkova. The Briton has captured their two most recent meetings without dropping a set, in the 2016 Stanford semifinals (en route to her first title) and in the third round of Cincinnati the following year.



Venus and Serena Williams flew the flag for American tennis once again on the 4th of July; Steve Tignor pays tribute to the iconic sisters for Tennis.com.

The second-round match between Lucie Safarova and Agnieszka Radwanska was a testament to longevity and love of the game, writes Briana Foust for Tennis With An Accent.

This year is the 40th anniversary of Martina Navratilova's first Wimbledon title - and, in an interview with Jon Wertheim for SI.com, the trailblazing legend of the sport discusses why it's even more important to be outspoken than ever.

In an increasingly globalized sport, more and more non-traditional tennis nations are rising to the fore, writes Vivienne Christie for Wimbledon.com - and among the national trailblazers are Tunisia's Ons Jabeur and Greece's Maria Sakkari.



Check out all of Day 1's scheduled women's matches on the WTA website here.

For full Order of Play and to watch live streaming, visit Wimbledon's official site.