Actually, during an interview, One already aswered that question:
ONE: "Garou vs Boros, who would win, you ask? Before (pre-monster Garou), it was quite obvious Boros was ways above him. But now that Garou has basically become the perfect monster, it is hard to tell who would win, it would've been one hell of a battle. I do believe that Garou is stronger in close combat, where he would simply dodge all punches and kicks"

Source (It's a link to all the translated interviews of One. Use CTRL + F and search Garou)

Do you think that the worthy opponent that was mentioned in the prophecy to Boros was actually Garou?