Teens Engel, Budkov Kjaer, Fonseca among five Challenger player storylines from 2025
From teenage breakthroughs to the reigning NCAA champion surging onto the pro stage and a historic title run in Africa, ATPTour.com recaps five Challenger player storylines from the 2025 season.
German teen Engel finishes as youngest champion of 2025
Fans in Hamburg witnessed a new German star emerge as Justin Engel stormed to his maiden ATP Challenger title on home soil.
At 18 years and 25 days, Engel became the youngest Challenger champion of the season and the fifth-youngest German winner in history. The #NextGenATP teen downed fellow 18-year-old Federico Cina 7-5, 7-6(4) in the final — the youngest championship match at that level since 2003, when Mario Ancic beat Rafael Nadal, also in Hamburg. Engel became the first player born in 2007 to win an ATP Challenger event.
“Every title is a big one, especially my first Challenger,” Engel said at the time. “Cina is a big player and I knew before the match it was going to be a tough match. This win makes it even better and I’m really happy.”
Zheng goes from NCAA champ to three-time Challenger titlist
College tennis players continue to excel on the Challenger circuit, including Michael Zheng, who won the 2024 NCAA singles title representing Columbia University and successfully defended his title last month.
Thanks to his collegiate success, Zheng qualified for the ATP Next Gen Accelerator, a programme that aims to increase the development pathway for top players in the American collegiate system to earn direct entry into select Challenger events. Zheng made the best possible use of one of his Accelerator spots at the Chicago Challenger in August, going all the way to the winner’s circle as World No. 416. Zheng then added to his title haul in September with consecutive trophies in Columbus and Tiburon.
“It’s definitely a super helpful programme,” the 21-year-old said of the Accelerator programme.
“It gives a lot of incentive for players to come to college and go through that pathway. You just get that jump start from your career… You have a good result like how I had in Chicago, then all of a sudden your ranking is there to get into the main draw of Challengers by yourself. I think it’s a great initiative.”

Michael Zheng is crowned champion at the Tiburon Challenger. Credit: Natalie Kim
Coulibaly’s historic title in Côte d’Ivoire
You could not script Eliakim Coulabily’s first Challenger title run any better. His home country, Côte d’Ivoire, hosted back-to-back tournaments and became the 95th country to host an ATP Challenger event — it was there in the capital city Abidjan where Coulibaly produced contrasting results, finishing with one of the most memorable moments of his career.
After an opening-round loss in the first week, Coulibaly swung freely and gave his home fans plenty to cheer about. Capping the title run with a three-set final victory, the Ivorian fell on his back in relief as the locals rose to their feet. Coulibaly became the first player from Côte d’Ivoire to win a Challenger title.
Reflecting on his full-circle journey, Coulibaly said, “Never stop believing, man. Never stop believing. I come from fire. I come from Africa. Being an African person and being able to try to make it on the ATP Tour is difficult. You don’t see many too many African players out there trying to play because it’s difficult. But for me it’s just discipline and never stop believing. It’s a tough journey for me.”
#NextGenATP Budkov Kjaer caps historic season, joins Gasquet, Rune and Coria in record books
Remember the name Nicolai Budkov Kjaer. The 19-year-old, who will be competing at this month’s Next Gen ATP Finals presented by PIF, was one of six players to capture a season-leading four Challenger titles. The Norwegian became the fourth-youngest player to accomplish that feat, alongside an elite trio of Richard Gasquet, Holger Rune and Guillermo Coria, all of whom spent time inside the Top 10 of the PIF ATP Rankings.
“You always want to believe you have the level to beat the guys at the top and I always had the belief that I’m a very dangerous opponent,” Budkov Kjaer said after winning his first Challenger title in Glasgow in February. He was also crowned champion in Tampere, Astana and Mouilleron le Captif.
Fonseca, Del Potro side-by-side in history
Across a meteoric rise the past 12 months since winning the Next Gen ATP Finals presented by PIF, Joao Fonseca made history in his ATP Challenger appearances. Just 13 days removed from his Jeddah triumph, the Brazilian won the Canberra Challenger, joining Jannik Sinner as the only players to win their ensuing tournament after claiming the 20-and-under event.
Then, at the ATP Challenger 175 event in Phoenix in March, Fonseca won his third trophy at that level and became the second-youngest player from South America — behind Juan Martin del Potro — to achieve that feat. Fonseca, who also won the ATP 250 in Buenos Aires and the ATP 500 in Basel, also became the fourth-youngest player to win an ATP Tour event and an ATP Challenger tournament in the same season. He stands alongside Kei Nishikori and three ATP No. 1 Club members; Carlos Alcaraz, Andy Roddick and Lleyton Hewitt as the five-youngest players to achieve the feat.

