Maria Sharapova's professional season might be winding down, but her boyfriend is kicking off ass-eatin' season ... in a big way!
The Russian tennis star was lounging in a bikini Sunday in Positano, alongside her millionaire bf, Alexander Gilkes, who decided to order lunch OFF-menu. For some reason, Alex got a face full of Maria's butt.
He was also pretty handsy with the booty -- so, there's little question to what he sees in Maria. Check out the pics, though ... she was stuck on her phone the whole time he was going to work back there.
We'd say she's gonna give the guy a complex, but looks like it's all love, baby.