In addition to this battle between two of the world's brightest 21-and-under stars, we're keeping our eyes on three other matches.

The ATP Challenger Tour has been an all-out battleground this year—here are five players who've risen up to the challenge.

The Serb has a chance to clinch year-end No. 1 for a record seventh time this week, depending on his and Daniil Medvedev’s results in Paris.

Jordan, Maxime and Andreas all needed final-set tiebreakers and saved a combined nine match points on a wild Tuesday afternoon.

If the 18-year-old can survive this tough test against the Hungarian, he has a legitimate chance to capture his second ATP title heading into the US Open.

It depends whether you value quantity or quality.

While Novak Djokovic is a heavy favorite, Marton Fucsovics has stolen a set in each past encounter.

Garin, Khachanov, Samsonova, Fucsovics, Golubic: watch out for this quintet.

The eighth-ranked Russian put another jewel in his ATP 500-level crown, while the 18-year-old Dane won her first WTA tour title.

After sharing a tight contest at Roland Garros last year, Rublev and Fucsovics will now meet for the ABN AMRO World Tennis Tournament trophy on Sunday.