Throughout the year, there were upsets that shocked fans and players alike; matches that made the world go "Wait...who won?!" As the season comes to an end, we take a look back at the 10 biggest upsets of 2019.

1

Coco Gauff vs. Venus Williams

Tournament: Wimbledon

Rankings: No. 313 vs. No. 44

Seeds: Unseeded vs. Unseeded

Head-to-Head:  First meeting

When fans think of the 2019 season, what will come to mind? Maybe it's the Big Three remaining at the top of the rankings, perhaps Bianca Andreescu winning the US Open, or Simona Halep winning Wimbledon.

All are solid choices, yet one shock defeat stands above the rest as not only the moment that defined this year, but perhaps the moment that will define the future of tennis: Coco Gauff versus Venus Williams in the first round of Wimbledon.

Everyone knew that Gauff was great; she wouldn't have made it passed the qualifiers if she wasn't. Yet it was still hard to imagine the 15-year-old beating the older Williams sister. She was unproven against the elite and, of course, had never stepped foot on the biggest stage in tennis, something that scares adults let alone a teenager.

Yet, in two sets, 6-4, 6-4, Gauff shocked the world. In fact, she didn't just win the first round, she continued through to the Round of 16 before finally being stopped by Halep. It was a transformative moment for not just Gauff, but, potentially, the next decade of the sport.

How could this match be put anywhere else, but at No. 1?