Here's Bryce Harper's 1-year-old son hitting a MOON SHOT home run off his toy tee ball set Wednesday ... and, yeah, safe to say Dad loves it!!!

The Philadelphia Phillies superstar's kid was getting in some hacks with his plastic baseball bat this week ... when suddenly, the little man fired off a rocket DEEP to left-center!!

Check out the swing ... little Krew Harper already has the one-handed follow-through down pat!

Bryce was impressed with his boy's ability ... writing of the clip, "That'll work."

The effort is pretty amazing ... Krew was only born in August 2019 -- so, only about 17 years to go until the MLB debut?!

By the way, baseball stars' infant sons crushing homers is becoming quite the thing in the MLB ... have you seen Freddie Freeman's kid with the bat??