Top 5 Photos, July 1: Teenage Gauff defeats Venus; Osaka knocked out

Day 1 at Wimbledon was full of twists and turns, upsets, and some usual suspects advancing to the second-round. These are the Top 5 photos from Monday's action.

1. Cori "Coco" Gauff seemed to play with no nerves as she rallied past one of her idols Venus Williams, 6-4, 6-4. The 15-year-old graced Centre Court for the first time with the utmost composure and controlled the match from start to finish. With her stunning victory, the wild card entry becomes the youngest woman to win a main-draw match at Wimbledon since 1991.

2. Novak Djokovic began his title defense with a win over Philipp Kohlschreiber, 6-3, 7-5, 6-3, to set up a second-round match against Denis Kudla. The world No. 1 skipped all grass lead-up tournaments this year, and the transition from clay to grass can be challenging even for the top players. The good news for the top seed is that he will not have to face a seeded opponent until the third round.

3. Yulia Putintseva upset world No. 2 Naomi Osaka, 7-6 (4), 6-2, for her third victory over the Japanese star. Osaka has lacked consistency since capturing the Australian Open title, and has battled with increased pressure and expectations. Putintseva helped Naomi lose the match on her own strings by just keeping the ball in the court.

4. Simona Halep edged past Aliaksandra Sasnovich, 6-4, 7-5, to advance on Monday. Halep, who reached the semifinals in 2014, called for treatment twice during the match after hyper-extending her left knee and spraining her ankle as she lost her footing while sliding on the turf. She will play fellow Romanian Mihaela Buzarnescu; the two have never played on the WTA match against each other.

5. After dropping a close first set, Felix Auger-Aliassime rose to the occasion and claimed his first Grand Slam win ever over fellow Canadian Vasek Pospisil. The No. 19 seed will play France's up-and-coming Corentin Moutet in the second round after Moutet ousted Grigor Dimitrov.