"It did not go well."
That's how Brooks Koepka's model GF described the way she cut the PGA Tour star's hair during quarantine ... and we gotta say, we agree -- but the whole process was at least funny as hell!!
The golf stud was in desperate need of a trim Thursday, so he handed over the clippers to Jena Sims ... and, after consulting with Koepka's barber and some YouTube vids, she went to work.
The problem? Things went sideways in a hurry ... Jena ended up quitting toward the end -- and the results of Koepka's new 'do were laughable.