Indy 500 Champ Alexander Rossi: Hey President Obama ... Where's My Phone Call?!

He's dialed up Super Bowl champs, Final Four winners and World Cup victors ... but the guy who won the Indy 500 wants to know when President Obama plans to blow up HIS cell phone!

TMZ Sports spoke with Alexander Rossi -- who took the checkered flag at the most iconic American car race of the year -- and he makes a pretty good case about why he deserves a call from POTUS.

"That's the most American thing we coulda done," Rossi says ... "100th running of the Indy 500 in Indianapolis? American won? I think that's pretty cool."

"So, Mr. President ... I'll be waiting."