Mark Cuban -- WNBA Is a GREAT Investment ... for Magic Johnson

Magic Johnson is going to SAVE the WNBA ... or at least the L.A. Sparks ... so says Mark Cuban who tells us if there's anyone who bring the team back from financial ruin, it's their new celebrity owner.

Shocking, considering the Sparks are BROKE ASS BROKE -- they haven't made a profit in years and were expected to lose another MILLION DOLLARS this season.

But that was before Magic and his ownership group stepped in ... and now Cuban (who knows a little something about investments) says it's the perfect move.

TMZ Sports: Do you think Magic can turn the Sparks into a success?
Cuban: "Yes yes yes. I love it. It will be great. Plus with his Dodgers ownership he will have a promotional platform."

Fun Fact -- the Sparks actually led the league in attendance over the past two seasons.