Novak Djokovic has had an up-and-down couple of seasons, but appears back to his best after making another piece of tennis history.
Sunday's straight sets win over Roger Federer in Cincinnati means that Djokovic is now the first man in history to claim victories in all nine Masters Series events.
Already the reigning Wimbledon champion, he's now completed the first "Career Golden Masters," a feat no other player has achieved since the series was formed in 1990.
"Great, great satisfaction and it's definitely one of the most special moments of my career," said Djokovic following the win over Federer. "Being the only player in history to win all Masters and Slams, it's definitely something that I'll be very, very proud of the rest of my life."
Victory in Cincinnati earned the Serb over $1 million in prize money and moved him up to sixth in the world rankings.
Djokovic's total winnings for the year now stand just short of $5.5 million, already more than double what he earned from playing tennis on court for the whole of an injury-troubled 2017.
By contrast, he made over $14 million in 2014 and 2016, but that was still some way short of his best season in 2015, when a dominant Djokovic amassed $21 million and won three of the four Grand Slams that calendar year.
Djokovic has consistently earned above $25 million annually for most of this decade from sponsorship alone, according to Forbes' annual World's Highest-Paid Athletes list. However, his earnings took a hit in 2017 as he struggled to make it to the latter stages of the year's biggest tournaments.
Despite the injuries and personal complications of the recent past, Djokovic has remained one of the sport's most bankable athletes. Last year, he switched clothing brands from Uniqlo to Lacoste, as part of a five-year deal worth a reported $9 million a year.
His other existing sponsorship deals include sports equipment manufacturer Head, ANZ bank and Jacob's Creek wine. However, the gap between Djokovic and 20-time Grand Slam-champion Federer in terms of commercial value is still vast, with the Swiss national estimated to make $100 million in 2018, according to business site Verdict, largely thanks to the $300 million clothing deal he signed with Uniqlo.
The 31-year-old Djokovic made a return to form earlier this year by winning his fourth Wimbledon crown and has now followed up that victory at an event where he had been a five-time runner-up previously, comprehensively beating seven-time champion Federer 6-4, 6-4 in the final.
Victory came at a 12th attempt for Djokovic in Cincinnati and it was his second title of the year. He will now look to take his form into the U.S. Open, which starts on August 27, having previously won two titles at Flushing Meadows in 2011 and 2016.