Greek tennis star Stefanos Tsitsipas admitted that being stubborn and not being willing to change some things cost him a victory in the 2021 French Open final. At the French Open last year, Tsitsipas reached his maiden Grand Slam final. Tsitsipas was playing world No. 1 Novak Djokovic in his first Grand Slam but he was showing no signs of pressure or anything like that early on as the Greek won the first two sets and put himself in a great position to win his first Grand Slam title. After falling down by two sets, Djokovic took a bathrom br …