The 36-year-old's whites were missing the usual swish and the familiar RF emblem were gone after the 20-times grand slam champion ditched long-term kit supplier Nike in favour of Japan's Uniqlo brand.
"They are my initials".
Roger Federer began the defence of his Wimbledon men's title in sensational style as he swept past Dusan Lajovic to reach the second round on opening Monday.
Many fans watching the Swiss maestro on court, however, simply couldn't come to terms with the fact he was no longer kitted out in Nike gear. "I remember I struggled early on a lot", said Federer.
Federer, the defending champion and seeking a 21st major, marked the start of his 20th successive Wimbledon with a new look and a comfortable 6-1, 6-3, 6-4 win over Serbia's Dusan Lajovic. "It's very exciting also again to see what's out there, who wants to do something with me".
In a statement, a spokesperson for Nike said they "do not comment on athlete contracts".
Reports earlier this month suggested that the 36-year-old was preparing to end his career-long association with Nike in favour of a ten-year deal with Uniqlo after seeing his deal with the United States sportswear brand expire in March. Uniqlo previously had a deal with Novak Djokovic, but the Serb has always worn Asics shoes.
On Sunday, he turned up at the traditional champion's pre-tournament news conference at the All England Club in a white shirt, grey blazer and navy pants instead of the usual tennis whites he has sported in previous years. Golfer Adam Scott and tennis star Kei Nishikori were its best known endorsers until Monday.