Top 5 Photos, July 4: Rafa's 50th Wimbledon win; Serena battles back

From an electric Centre Court showdown to the start of a doubles campaign for a home hero, Day 4 at Wimbledon was full of fireworks. These are the Top 5 photos from Thursday's action.

1. Rafael Nadal soared in a tight match that lived up to its billing. Nick Kyrgios ousted the French Open champion earlier this year and made Nadal work for the second-round victory. The Spaniard kept his composure. handling the pressure to claim his 50th win at Wimbledon. 6-3, 3-6, 7-6 (5), 7-6 (3).

2. Meghan Markle, The Duchess of Sussex, made a surprise appearance on Thursday to watch her good friend Serena Williams. This wasn't Markle's first time at this event: she stopped by in 2016 around the same time she was set up on a blind date with her now husband, Prince Harry, and attended the event last year with sister-in-law Kate Middleton, which marked their first joint event together.

3. It took an entire set for Williams to find her game, but once she did, she asserted herself to defeat qualifier Kaja Juvan, 2-6, 6-2, 6-4. The 23-time Grand Slam champion will face Julia Goerges in the third round and holds a perfect 4-0 head-to-head record against the German.

4. Lucky loser Lauren Davis sprung a major surprise by ousting reigning Wimbledon champion Angelique Kerber, 2-6, 6-2, 6-1. Davis twisted her left ankle in the middle of the first set and remarkably recovered to claim arguably the biggest win of her career. She will continue her grass-court campaign against Carla Suarez Navarro for a chance to reach the second week of a major for the first time.

5. Dropping the first set wasn't enough to deter Andy Murray and Pierre-Hugues Herbert from winning their first-round encounter against Marius Copil and Ugo Humburt. After taking some time to gel, the two came together nicely to advance, 4-6, 6-1, 6-4, 6-0. Murray, who won Queen's Club with Feliciano Lopez two weeks ago, hasn't played more than five doubles tournaments in a year since 2014.