Roger Federer v Dusan Lajovic
Federer leads series 1-0
World number 57 Lajovic gave Alexander Zverev a huge fright at the French Open by taking a two sets to one lead before folding in five. Best run at the majors was a last-16 spot at Roland Garros four years ago where it took Rafael Nadal to stop him. The Serb was beaten by Federer in straight sets in the second round of Wimbledon in 2017.
Rafael Nadal v Dudi Sela
Nadal leads series 2-0
Ranked 129, the 33-year-old Sela has just three wins on the main tour in 2018 but made the last-16 at Wimbledon in 2009 where he was knocked out by Novak Djokovic. Also made the third round last year where injury forced him to quit against Grigor Dimitrov. At 5ft 9ins (1.75m), the Israeli jokes that "if I had 10 more centimetres I'd have success at tennis".
Novak Djokovic v Tennys Sandgren
World number 56 Sandgren of the United States stunned the sport by making the Australian Open quarter-finals in January knocking out Stan Wawrinka and Dominic Thiem. He also caused a storm for his alleged support of right-wing groups, something the devout Christian denied. "You seek to put people in these little boxes so that you can order the world in your already assumed preconceived ideas. You strip away any individuality for the sake of demonising by way of the collective," the 26-year-old told reporters in response. Made the final in Houston this year but will be making his Wimbledon debut.
Andy Murray v Benoit Paire
Murray leads 2-0
Explosive and colourful, the 29-year-old Paire was a point away from beating Federer in the Halle second round this month. Famously kicked out of the 2016 Rio Olympics for breaking team rules while, two years earlier, the Frenchman said he hated Wimbledon. "The atmosphere displeases me greatly," he said. Despite that, still made the fourth round at Wimbledon in 2017 where he lost to Murray.
Serena Williams v Arantxa Rus
Dutch world 107 Rus made the third round at Wimbledon in 2012 but failed to get out of qualifying on her last three visits. Made the quarter-finals in Auckland and Istanbul this year, she is a former Australian Open junior champion.
Simona Halep v Kurumi Nara
Halep leads series 1-0
Nara, standing at just 5ft 1in (1.55m) is ranked 101 but the Japanese has a Grand Slam pedigree -- in 2017, she defeated two-time major winner Svetlana Kuznetsova in the second round of the US Open. Made the third round on her Wimbledon debut in 2010 after coming through qualifying. Never one to do things the easy way, in 2016 Nara tried to fly to Charleston, South Carolina for a tournament, only to land at Charleston, West Virginia -- 640km to the north.
Garbine Muguruza v Naomi Broady
Muguruza leads 1-0
British wild card Broady, ranked 138, has just one win on the WTA Tour this year, playing mostly on the ITF circuit. It was on that second-level that Broady faced 2017 Wimbledon champion Muguruza in their only meeting at Wrexham in Wales in 2011. Has played six times in the Wimbledon main draw with just one victory in 2014 before a second round exit at the hands of Caroline Wozniacki.
Maria Sharapova v Vitalia Diatchenko
Sharapova leads 1-0
Ranked at 132, the 27-year-old Diatchenko has been plagued by injuries. This year, the Russian qualified for Wimbledon and returned to the main draw of a major for the first time since the 2016 US Open. Has never won a main draw match at Wimbledon.