WATCH: A tribute to Roger Federer on his 36th birthday

A long-held belief has been that, after 30, tennis players gradually begin to leave their primes and fade into the distance. Over the past few years we’ve seen that theory debunked time and time again, and perhaps never more so than in 2017.

Roger Federer turned 36 on Tuesday, and in what should be the twilight of his career, he’s having one of his most unbelievable and, frankly, incomprehensible seasons.

Coming into his opener in Montreal this week—he’ll play Canadian wild card Peter Polansky—the Swiss legend, who missed six months in 2016 after undergoing knee surgery, holds a 31-2 record with titles in Indian Wells, Miami and Halle and Grand Slams No. 18 and 19 at the Australian Open and Wimbledon.

He’ll go for No. 20 in New York later this month.

Above, relive some of the living legend’s most memorable moments in a career that’s been unmatched, and most likely always will be.

—Citi Open Women’s Semis/Final: Catch up on all the action from Citi Open on Tennis Channel Plus.

—Citi Open Men’s Semis/Final: Take a look back at the best matches from the Citi Open with on demand match coverage on Tennis Channel Plus.

—Azarenka Channel: Enjoy the best moments from Victoria Azarenka on the Azarenka Channel exclusively on Tennis Channel Plus.

—Sharapova Channel: Gear up for Maria’s return to next week’s Cincinnati Open with the Sharapova Channel only on Tennis Channel Plus.

—Get Tennis Channel Plus for 650+ live events all year long.

—Tennis Channel Plus is available on any streaming device, on mobile, always on the GO (desktop, iOS, Android, Apple TV, Roku and Amazon Fire). Subscribe today at BuyTCPlus.com.