Guinot and IMG declined to comment for this article.
Players are offered a few thousand dollars per patch, which are pre-made and bear the corporate logo. The amount increases based on the player’s ranking and round of the tournament, stopping around $10,000. Three players have won Grand Slam titles wearing Guinot patches: Svetlana Kuznetsova, the 2004 U.S. Open and 2009 French Open champion; Samantha Stosur, who won the 2011 U.S. Open; and the 2013 Wimbledon champion Marion Bartoli.
Rules for the size and placement of corporate logos on tennis outfits are strict, especially at Grand Slam events. Only two patches are allowed, neither of which can exceed six square inches. When a Guinot-sponsored player has room for just one logo, they wear the Guinot brand patch. When they have room for two, a patch for Guinot’s brand Mary Cohr is added. Players iron or sew them on themselves, or take their outfits to the on-site tournament tailor to have them applied.
The system is foolproof — almost.
At the 2015 Australian Open, Tim Smyczek, ranked 112th, received a deal to wear the patches when he played Nadal, and dropped off eight shirts to be sewn by the tournament tailor.
Only five of his shirts got the patches, however. The match then proved surprisingly competitive, with Smyczek forcing Nadal deep into a fifth set. By the time he reached the critical final moments of the match, Smyczek had sweat through all of his shirts with Guinot patch, and finished the match wearing a shirt without one.
“I wonder if you go back and look at the winning percentage wearing those patches, it’s got to be the all-time least winning patch on a sleeve, for sure,” Smyczek said. “But yeah, I remember just thinking I might not win this match, but here’s a nice little bonus I could go home with.”
Over the first six days of this year’s U.S. Open, six players — Radu Albot, Timea Babos, Viktoria Kuzmova, Dusan Lajovic, Feliciano Lopez and Elise Mertens — wore Guinot patches. All lost. The seventh proved lucky on Sunday, with Anastasija Sevastova beating Maria Sharapova to reach the quarterfinals.
Other brands target top players with more lucrative long-term contracts meant to showcase their brands. Porsche sponsors last year’s U.S. Open champion Angelique Kerber, and she wears their logo on her tops.
Viktoria Wohlrapp, a spokeswoman for Porsche Tennis, said Porsche found that the majority of the deal’s value came from matches Kerber played at Grand Slam events. Ms. Wohlrapp said she admired Guinot’s approach.
“In general, it’s a great idea to get good exposure without a too-long commitment, marketing-wise,” Ms. Wohlrapp said. “Patches are sometimes risks: you pay for something, and you don’t get the return on it, because the player is not playing that well, so it doesn’t get the exposure you would like to.”
Ms. Wohlrapp said Guinot’s strategy would not be appropriate for Porsche, however.
“For Porsche, our main goal was never to have brand exposure, but to emphasize the partnership between the brand and the athlete,” she said. “That’s what our main goal is; we wouldn’t put patches on every athlete just to get the exposure.”
Some clothing companies also prohibit their athletes from wearing other companies’ logos. Nike forbids its sponsored athletes, with the exception of some from China, from wearing other logos on their clothing. A handful of top tennis players have similar deals with other apparel companies. When Caroline Wozniacki last renegotiated her deal to wear Adidas’ Stella McCartney line, she was paid a premium for agreeing to keep her outfit free of patches, called a “clean” contract.
“I think it’s much better looking,” Wozniacki said of her patch-free outfits. “But at the same time, it also has to make financial sense, so it’s kind of a give and take. But if you can make it clean and make it work financially, I think that’s the best of both worlds.”
A few players have resisted the offers for other reasons. Kuznetsova, who won two Grand Slam titles wearing the patches, says she now sees herself “as a brand” and would accept only longer-term offers.
“All the respect for whoever wears them, it’s good money and stuff,” she said.
The retired player Mardy Fish said he had always rejected one-match offers.
“Whenever I endorse a company, I want to know who it is, what’s behind it, who they are,” Fish said. “I wanted it to look good, to be on my shirt, to be part of the company, a member of the team, so to speak. I’m sure I’m a rare case, because it is easy money.”
Fish’s hesitation does seem to be rare. Sam Querrey, for example, wore a Guinot patch in his Wimbledon quarterfinal win this year over the top-seeded Andy Murray, but replaced it in the semifinals with a patch from Wheels Up, a private aviation company that compensates him with money and the use of its jets.
“You literally just go with who pays you the most; I don’t care what’s on there,” Querrey said. “I just put it on and get paid, that’s all I care about. I don’t even know what Guinot and Mary Cohr are.”