Seiko's watch partner since January 2014, he was given an Astron GPS Solar at the signing and has his own line of signature Astron GPS Solar editions. He does not play in it but puts it on after the match and before receiving awards, as at Wimbledon 2018 and the 2020 Australian Open (2020 limited edition).
21 mm
Most common strap size on this line: 21 mmSource: Novak Djokovic official site, Forbes, A Timely Perspective
