Novak Djokovic paid tribute to late basketball star Kobe Bryant after he won his record-equalling 24th Grand Slam title at the US Open on Sunday, wearing a "Mamba Forever" shirt during the trophy presentation.

Djokovic beat Daniil Medvedev 6-3, 7-6 (7/5), 6-3 to clinch his fourth US Open crown and gain revenge for his loss to the Russian two years ago which shattered his dreams of a calendar Grand Slam.

Afterwards Djokovic revealed a t-shirt with an image of him alongside Bryant -- the ferociously competititve basketball great whose nickname was "Mamba". On the back was 24, the number worn by the Los Angeles Lakers icon during his NBA career.

Djokovic said Bryant, who died in a helicopter crash three years ago, had helped him through some of the most challenging times of his career -- notably a career-threatening elbow injury in 2017.

"I thought about doing this t-shirt a few days ago," said Djokovic.

"I didn't share it with anybody. Kobe was a close friend of mine, we chatted a lot, about the winner's mentality.

"When I was struggling with injury and trying to work my way back to the top he was one of the people I relied on the most he was always there for support in the most friendly way.

"His passing hurt me deeply and 24 is the jersey he wore at Lakers so I thought it would be nice to acknowledge him."