'mail it in'

Hi,
This time it’s from an American for sure. And set off with quotation marks too. No hiding the fact its usage is a kind of unconventional.
Close to ‘bottle it out’ to me. And how about parallels: ‘mail it in’—‘throw in the towel’?

“The Serb is now without a major title after holding all four 12 months ago.
“I don’t recall seeing a time in the last six to eight years when he [size=150][color=darkred]‘mailed it in’[/size],” McEnroe told BBC Sport.
The American, a seven-time Grand Slam singles champion, added: “He basically gave up.””

Never heard it, but then it is an American idiom.

en.wiktionary.org/wiki/mail_it_in
urbandictionary.com/define.p … %20it%20in
uncyclopedia.wikia.com/wiki/Mailing_it_in

Yes, a similar idiom is “going through the motions”.

Thank you.

‘Half-ass’ also has a nice ring to it.