Jannik Sinner of Italy holds the Norman Brookes Challenge Cup after defeating Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner, right, of Italy holds the Norman Brookes Challenge Cup after defeating Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy poses with the Norman Brookes Challenge Cup and ball kids after defeating Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy celebrates after defeating Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy, left, greets Alexander Zverev of Germany after Sinner's win in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy celebrates after defeating Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy plays a forehand return to Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Alexander Zverev of Germany reacts during the men's singles final against Jannik Sinner of Italy at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy plays a forehand return to Alexander Zverev of Germany in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Alexander Zverev of Germany reacts during the men's singles final against Jannik Sinner of Italy in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Alexander Zverev of Germany, center top, and Jannik Sinner of Italy play during the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Alexander Zverev of Germany plays a backhand to Jannik Sinner of Italy in the men's singles final at the Australian Open tennis championship in Melbourne, Australia.

Jannik Sinner of Italy plays a forehand to Alexander Zverev of Germany during the men's singles final at the Australian Open tennis championship in Melbourne, Australia.