Summary
Stefanos Tsitsipas said he was ready for a breakthrough Grand Slam victory after winning the ATP Finals in London -- but a glance at recent history invites caution. The 21-year-old Greek was in a bullish mood after he beat Dominic Thiem, having ousted Roger Federer in the semifinals, to become the season-ending event's youngest winner since 2001 .
Last year, young German Alexander Zverev pummeled Novak Djokovic in the final but he had a miserable time at this season's Grand Slams -- while the Serb, 32, picked up the Australian Open and Wimbledon titles to take his overall tally to 16 .
No member of the "Big Three" -- also featuring Federer -- has won the season-ending ATP Finals since 2015, when Djokovic picked up his fifth title.
Djokovic was also the last ATP Finals champion to go on to win a major title.
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