During his match against Florian Mayer in Hamburg, Roger Federer casually added a Nike sweater vest to his match attire after taking the first set.

Twitter reacted calmly and rationally to this new development.

oh mY GOD HE'S WEARING A SWEATER VEST HE'S WEARING A FUCKING SWEATER VEST AHAHAHAAAAA — Maisie (@goderer) July 19, 2013

Oh my god. Federer is actually wearing a sweater vest while he plays. I cannot. — Jennifer Desiree (@jfratzy) July 19, 2013

@AmyFetherolf I had the same reaction except a few more hahas — Nick Nemeroff (@NNemeroff) July 19, 2013

Sweaterer is looking like one of the 50+ men at my local tennis club. He's playing that first game a bit better than them though. — RenÃ© (@Renestance) July 19, 2013

Roger is wearing a sweater vest. — Chris P (@scoobschris) July 19, 2013

Roger Federer in a sweater vest is quite frankly the most amazing thing to happen to this world. Laughing like a maniac rn. — Sweaterer Vesterer (@grass_courts) July 19, 2013

I'm in stitches. This is too much, Roger. — David (@david93_do) July 19, 2013

I actually cannot get over the sweater vest. I am STILL laughing. — Jennifer Desiree (@jfratzy) July 19, 2013

How insulted must Flowery feel? …. Fudd believes he can go into Grandpa mode and still beat him — ton skeel (@naughtyT) July 19, 2013

This is FULL ON Grandpaps tennis right now…. — Robin Hosking (@robinsportweet) July 19, 2013

Federer looks funny! A little like my late grandpa! 😀 — Prashant Paul (@prashantsport) July 19, 2013

FEDERER IS WEARING A SWEATER VEST IM DYING LAUGHING — EED (@Well_its_evan) July 19, 2013

Oh man, Nike is really going after the retirement village demographic. — Lindsay Gibbs (@linzsports) July 19, 2013

1974 Jimmy Connors thinks there's nothing overly unusual about Federer's attire: http://t.co/MhrNIhrWxl — Matt Zemek (@mzemek) July 19, 2013

I hope on changeovers he brings out a pipe & slippers. Finds himself a rocking chair. Maybe grabs a bag of Werther's Originals. 🙂 — Rhian (@rosso_neri) July 19, 2013

Or is that Chandlerer Bingerer — Chris P (@scoobschris) July 19, 2013

The Federer casually putting on a sweater vest before the beginning of the 2nd. Because of course he did. — Robert (@jamogardens) July 19, 2013

what on God's green Earth is Federer wearing? — Ricky Dimon (@RD_Tennistalk) July 19, 2013

Roger didn't move to that dropshot. Then again, he thought he was playing shuffleboard now. — Chris P (@scoobschris) July 19, 2013