Willett shows ads still pay at Masters

England's Danny Willett waves wearing the Green Jacket at the end of the 80th Masters Golf Tournament at the Augusta National Golf Club on April 10, 2016, in Augusta, Georgia

The Masters is one of the most advertising-free zones in sport -- but reigning champion Danny Willett is living proof that there are still millions to be made.

The Englishman's sponsors picked up $7.7 million (7.25 million euros) of free advertising during his four-day onslaught to pick up the Masters' green jacket last year, according to the Nielsen Sports data firm.

That was more than 70 percent of the advertising value of $10.9 million that Willett generated over the season for his backers.

A study by Nielsen even pinned down which parts of his equipment produced most advertising benefit.

It said 55% of the value came from Willett's shirt, 38% by his hat, 4% from his equipment bag while 2% came from his eye-wear.

The $10.9 million figure is the estimated amount that Willett's sponsors would have had to pay to get equivalent advertising on television.

"Although Augusta is relatively free from branding during the tournament, the Masters still generates significant value for sponsors," said Glenn Lovett, Nielsen Sports global managing director

Nielsen said that because the Masters is "relatively free from sponsorship" brands that do get their name seen or mentioned get a huge advantage.

The Masters is "a tournament which still manages to deliver huge successes for sponsoring brands which do appear, in most cases enjoying a greater media value thanks to the lack of competition on screen, due to the lack of sponsorship signage."

Brand name space on balls, clubs, trousers and eye-wear are all avidly fought for.

"If it rains in the 2017 tournament branded umbrellas could well play a critical role for savvy brands," said Nielsen.