Challenger to Champion: How it all began for Carlos Alcaraz, Jannik Sinner and other ATP Tour stars

Big fans of Jannik Sinner and Carlos Alcaraz should be able to name all the Grand Slam tournaments they've each won. Diehards might even rattle off all of their Masters 1000 victories, and maybe even their first trophies on the ATP Tour, period.

But can even the biggest Sinner supporters and Alcaraz acolytes name the titles these two titans won before they hit it big, on the ATP Challenger Tour?

Challenger championships don't compare to what these stars would go on to achieve, but they were essential in building confidence and amassing experience. When you haven't yet won Wimbledon, winning an ATP Challenger Tour event for the first time can feel just as significant.

Over the past few months, we caught up with some of the most celebrated Champions in men's tennis—and spoke to them about when their very first triumph, as a Challenger.

Carlos Alcaraz

📍First ATP Challenger Tour title: Trieste, Italy (August 2020)

• Qualified for the tournament and won seven matches overall
• Defeated 321st-ranked Tomas Martin Etcheverry in the quarterfinals and 280th-ranked Lorenzo Musetti in the semifinals
• Won two more ATP Challenger Tour titles in 2020 (Barcelona, Alicante) and another the following May, in Oeiras

👉 Click here and listen to Alcaraz in Challenger to Champion on the Tennis Channel app

Alexander Bublik

📍First ATP Challenger Tour title: Morelos, Mexico (February 2017)

• Defeated 311th-ranked Nicolas Jarry in the final, 7-6 (5), 6-4
• Has won seven ATP Challenger Tour titles overall
• Played two ATP Challenger Tour tournaments in 2025; lost to Joao Fonseca in the Phoenix final

👉 Click here and listen to Bublik in Challenger to Champion on the Tennis Channel app

Jannik Sinner

📍First ATP Challenger Tour title: Bergamo, Italy (February 2019)

• Defeated three Italians en route to title (highest ranked: No. 151 Gianluigi Quinzi; in final: Roberto Marcora)
• In his very next ATP Challenger Tour match, he lost to Carlos Alcaraz, 6-2, 3-6, 6-3, in Alicante (CLICK HERE to stream replay)
• Has played 18 ATP Challenger Tour events, and won three

👉 Click here and listen to Sinner in Challenger to Champion on the Tennis Channel app

Jakub Mensik

📍First ATP Challenger Tour title: Prague, Czech Republic (May 2023)

• Defeated 149th-ranked Dominik Koepfer in final, 6-4, 6-3
• Faced his highest-ranked opponent that week—No. 112 Radu Albot—in first round
• Lone ATP Challenger Tour title

👉 Click here and listen to Mensik in Challenger to Champion on the Tennis Channel app

Stefanos Tsitsipas

📍First ATP Challenger Tour title: Genova, Italy (September 2017)

• Played 29 ATP Challenger Tour events before this breakthrough victory
• Defeated 123rd-ranked Guillermo Garcia-Lopez in the final, 7-5, 7-6 (2)
• Also defeated 49th-ranked Jan-Lennard Struff in quarterfinals, and led Marton Fuscovics 6-0, 1-0 in the semis before the Hungarian retired

👉 Click here and listen to Tsitsipas in Challenger to Champion on the Tennis Channel app

Stay tuned to TENNIS.com for more editions of Challenger to Champion. And watch this week's ATP Challenger Tour showcase events, in Aix-en-Provence and Cagliari, on the Tennis Channel app.