India, July 3 -- Coco Gauff spent a few moments staring at the baseline a few inches away from her, shell-shocked. Her serve had been sent back with a full-blooded inside-out forehand that eluded her stretched racket.

At the other end of the court, Dayana Yastremska emptied her lungs in a roar that marked the biggest win of her career. The Ukrainian had just beaten the world No.2 and with it, pulled off the biggest upset at Wimbledon this year.

By the time Gauff stepped on the No.1 Court at the All England Club, fans at Wimbledon had already been left stunned with the first round exits of World No.3s Jessica Pegula and Alexander Zverev. Pegula lost to Elisabetta Cocciaretto, who watched Wimbledon last year while in hospital. Zverev lost...