'Jerry Maguire' Kid Las Vegas Pick-Up Artist

10/26/2011 12:40 AM PDT

'Jerry Maguire' Kid -- Las Vegas Pick-Up Artist

"Family Guy" got it all wrong -- it's been 15 years since "Jerry Maguire," but ex-child actor Jonathan Lipnicki's still got the magic touch ... pulling seriously hot tail in Vegas last weekend for his 21st birthday.

You may recall -- "Family Guy" blasted Lipnicki in an episode last year, implying the once-adorable child actor had grown up into something ... less than attractive.

But that just ain't true ... because according to sources at XS Nightclub in Vegas -- where Jonathan celebrated his 21st on Saturday -- the actor had absolutely no trouble attracting several fine females. (exhibit a, above).

No word on what he used for his opener -- but we're guessing it went something like ... "Do you know that the human head weighs 8 pounds?" Works every time.