In July 2022, Ivanov competed in the inaugural
boys' U14 event at
Wimbledon, where he lost in the semifinals to the eventual champion, Korean Se Hyuk Cho. Ivanov had successful results on the
ITF junior circuit, maintaining a 106–35 singles win-loss record. In January 2024, He made his major jr. debut at the
Australian Open, where he lost in the first round in singles and the second round in doubles. In April 2025, Ivanov won the boys' singles category at the J300 Tournoi de Tennis ITF Junior in
Beaulieu-sur-Mer, France, defeating Ludvig Hede in the final. He also earned the trophy in doubles, playing with
Thijs Boogaard – the pair defeated fourth seeds Alejandro Arcila and
Karim Bennani in straight sets. The following month, the Bulgarian was a runner-up at the prestigious J500
Trofeo Bonfiglio in
Milan, losing to fifth seed and home favourite
Jacopo Vasamì in the final. In June, Ivanov fell short of reaching his first major jr. final, losing to eventual champion
Max Schönhaus in the singles semifinals at the
French Open, where he also reached the quarterfinals in doubles with Boogaard. At the
2025 Wimbledon Championships, Ivanov did not lose a set on his way to his first major jr. title, defeating 13th seed Schönhaus and then qualifier Ronit Karki in the final. With this feat, he became the second Bulgarian tennis player to win a boys' singles major title, after
Grigor Dimitrov, who won
Wimbledon and the
US Open in 2008. As a result, Ivanov reached an
ITF junior combined ranking of No. 1 on 14 July 2025. As the top seed at the
2025 US Open, Ivanov made a third consecutive major jr. semifinal with wins over Maximus Dussault and eighth seed Schönhaus. He reached a consecutive junior final with a win over Kazakh Zangar Nurlanuly in straight sets. He earned the title after defeating compatriot
Alexander Vasilev in straight sets. The match made history as the first all-Bulgarian major final ever. In December, Ivanov was named the 2025 world junior champion by the ITF. At 17 years old, he was the first Bulgarian to finish the season as world No. 1 in the junior rankings. He has won five singles and four doubles junior titles overall. ==Professional career==