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When Jack Sock isn't preoccupied pulverizing forehands on the tennis court, he packs quite a punch in the ring.

Watch: Ball Dogs Bounding in Brazil

The world No. 18 looks like a legitimate contender in this Instagram post he shared of his boxing workout.

 

thanks to my man @cmichaelyabut for the workout at Title 🥊 #CatchMeOutsideHowBoutDat

A post shared by Jack Sock (@jack.sock) on

Mar 3, 2017 at 6:34pm PST

Maybe Madison Square Garden will cue up the Rocky theme when Sock enters the ring, er, court to square off against sometime doubles partner Nick Kyrgios at the BNP Paribas Challenge tonight.

Sock joins Venus Williams, Juan Martin del Potro and Andy Roddick on Team America that takes on the Rest of the World Squad led by Kyrgios, Garbine Muguruza, Kei Nishikori and Lleyton Hewitt.

 

📸 @ashleymarshallsport | Tennis players from around the 🌎 unite #PlayForLife #USTAinfluencer #WorldTennisDay #squadgoals #VenusWilliams #JackSock #GarbineMuguruza #DelPotro #AndyRoddick #KeiNishikori #NickKyrgios #LleytonHewitt #BNPParibasShowdown #TeamAmericas #TeamWorld #letsgetreadytorumble #SuperAmadeo #superhero #tennisplayer #tennis @usta @jwmessexhouse

A post shared by NJTL Chapter | USTA Member (@tnnskids) on

Mar 5, 2017 at 8:07pm PST

 

Thank You @k1ngkyrg1os for helping me to get @jack.sock attention that's what teammates are for 😉😂💪Amazing event Thank You @usta and @worldtennisday for this one in a lifetime opportunity- so awesome 🎾💯 P.S I just realize Mr. @delpotrojuan walked by us 👋 #ustainfluencer #playforlife #interview #news #nickkyrgios #jacksock #bnpparibasshowdown #proudtoplaytennis

A post shared by Tennis Message (@tennismessage) on

Mar 5, 2017 at 7:34pm PST

 

 

Look who DelPo found yesterday in New York ... his 'amigo' Andy Roddick 👬 #DelPoInNewYork #DelPoAndARod #WorldTennisDay

A post shared by 🎾 J. M. del Potro Fanpage 🎾 (@delpoarmy) on

Mar 5, 2017 at 10:54pm PST

 

Happy @worldtennisday! Tune-in as we cheer on the Americas team: #AndyRoddick, @venuswilliams, @delpotrojuan & @jack.sock vs. World team: @lleytonhewitt89, @garbimuguruza, @k1ngkyrg1os & @keinishikori tonight at 7pm at @thegarden. __ #WorldTennisDay #PlayForLife #USTA #Tennis #TennisPlayer #InstaSports #NYC

A post shared by US Open (@usopen) on

Mar 6, 2017 at 9:06am PST

 

Happy #WorldTennisDay! Where are you playing today? 🎾

A post shared by Wilson Tennis (@wilsontennis) on

Mar 6, 2017 at 8:13am PST

The BNP Paribas Showdown exhibition is part of World Tennis Day. Here's a look at the MSG commercial promoting tonight's event.



ESPN2 will televise a two-hour encore presentation of the event on tape delay on Tuesday night at 11 p.m. Eastern time.

Photo credit: Delray Beach Open