The field for the 2025 Next Gen ATP Finals has seen a late but significant change, with German teenager Justin Engel joining the prestigious 20-and-under event following the withdrawal of Czech star Jakub Mensik.
Mensik, the highest-ranked qualifier for the tournament and a former Miami Open champion, pulled out due to medical reasons. This opened the door for the 18-year-old Engel, the youngest player in the field, who will make his debut at the season-ending championships for the world’s best young players. Engel made history in 2025 by becoming the first player born in 2007 to win an ATP Challenger Tour title.
The groups are set ??
Who will be the 2025 #NextGenATPFinals champion? pic.twitter.com/XJyfhDKSbU
— Next Gen ATP Finals (@nextgenfinals) December 14, 2025
Tien Emerges as Top Favorite
The absence of both Mensik and last year’s champion, João Fonseca (who also withdrew), has elevated American Learner Tien to the status of top seed and firm favorite for the title at the Next Gen Finals betting markets.
- Tien, the runner-up in Jeddah last year, has had a breakthrough 2025 season.
- The American lefty started the year outside the Top 120 and has climbed to a career-high ranking of No. 28.
- His impressive year includes winning his first ATP Tour title in Metz and reaching the final of the ATP 500 event in Beijing.
The tournament, which features experimental rules, is set to take place from December 17-21. Tien headlines the Blue Group, while Belgian Alexander Blockx leads the Red Group. All eyes will be on Tien to see if he can cap off his stellar season by lifting the Next Gen trophy.