Alexander Zverev made tennis history on Monday, 2 November 2026, becoming the 30th player ever to reach World No. 1 in men's singles — a milestone made all the more remarkable by a Type 1 diabetes diagnosis he has carried since the age of four. In a personal note published on the ATP website, the German star reflected on how the illness, and his mother's fierce refusal to let it define his future, shaped the champion he has become.

A Historic Rise to the Top

Zverev's ascent to the summit was built on a dominant 2026 season. He claimed his first two Grand Slam titles this year — Roland Garros and the US Open — to complete a long-anticipated breakthrough at the Majors level. At 29 years and six months, he is the second-oldest player to reach World No. 1 for the first time, behind only John Newcombe, who topped the rankings at 30 years old in 1974. Zverev also secured the coveted year-end No. 1 spot, capping a calendar year of extraordinary depth. He is already an Olympic champion, a two-time ATP Finals winner, and a 26-time tour-level title holder.

The Diabetes Diagnosis That Could Have Ended It All

Zverev was diagnosed with Type 1 diabetes at the age of four. Doctors, he recalled, told his family that a professional sports career would be 'nearly impossible' — words his mother, Irina, refused to accept. She shielded her young son from those medical conversations entirely. 'My mom would send me out of the room during those conversations, because she did not want me to hear what was going on,' Zverev wrote. To manage the condition during matches, he takes injections and monitors his blood sugar levels — a routine that began in his earliest school years.

'I don't want to say living with Type 1 diabetes helped me in my tennis career, or in life in general. But it definitely made me grow up a bit quicker than I probably would have done without it,' he said. The discipline required to manage a chronic illness from childhood, he suggested, built a resilience that his rivals without such pressures may not have needed to develop as early.

The Role of His Mother, Irina

With his father, Alexander Sr., and older brother, Mischa, frequently away on junior tour commitments, Irina became the central figure in Zverev's formative years — both as a parent managing a child's diabetes and as his tennis coach until the age of 16. 'When that happened, my mom said, 'Okay, he's still going to be able to play tennis. He's still going to be able to achieve the dreams that he has',' Zverev quoted her as saying. He credited that unflinching belief as the reason he entered adulthood with no doubt about his own potential. 'Because of that, I never really had any doubt that I could achieve anything, and that was thanks to having a very strong mother by my side,' he wrote.

A Ranking Dedicated to Diabetic Families Worldwide

Zverev was candid about the circumstances of the ranking change, acknowledging that current World No. 1 Jannik Sinner's injury played a part. 'It's a weird circumstance because of Jannik's injury. This is not the way that you want to reach the top of the sport,' he admitted. But he framed the achievement in terms larger than himself, connecting it to the Alexander Zverev Foundation, which he established to support children living with diabetes. 'Most importantly, I feel like me being World No. 1 is extremely important to a large group of people who have the same issues with diabetes. This is not about me,' he wrote. He concluded with a message of hope: 'Everything is possible and you will be able to live a fulfilled life with it. I'm proud as a Type 1 diabetic to show that to families dealing with the disease.'

What Comes Next

With two Grand Slams, a year-end No. 1, and a personal narrative that resonates far beyond sport, Zverev enters the final stretch of 2026 as the face of men's tennis. Whether he can sustain the top ranking into the 2027 season — and defend his Slam titles — will be the next chapter of a story that has already defied what doctors once thought possible.