Dustin Johnson Hits Bystander With 300-Yard Drive, 'There'll Be A Nasty Bruise'

FORE LEFT!!!!!!!!!!!!!!!!!

Dustin Johnson's wayward tee shot Friday missed its target by so much ... it pegged a bystander right in the back -- but, thankfully, the dude somehow survived the golf ball attack.

The insane scene all went down in Saudi Arabia at the Saudi International golf tournament ... where DJ was teeing off on the Par 4, 10th hole.

Johnson -- the 2020 Masters champion who's known as one of the most powerful drivers in the game -- hit his shot and immediately saw it go left.

With no fans in attendance due to the pandemic ... no real issue, right?

WRONG -- 'cause somehow Johnson's tiny ball found the square of a man's back ... and the dude crumpled in pain!!!

FYI, this could have been disastrous ... people have been seriously injured by wayward shots on the course before -- remember in 2018 when a woman claimed her eyeball exploded after being hit by a Brooks Koepka shot??

Fortunately, the guy got up okay on Friday ... shaking off the stinger and rubbing his back.

"He's just fine," one of the announcers said ... before adding, "There will be a nasty bruise."