Wait till he will attack you (glow red) then hit B twice to avoid it. Try to get behind him by rolling and then attack. If you will get behind him you can get 2-3 hits, if you will get in front of him just 1. When Glott will get to 50% he will start charging at you and glow yellow - hit Y to throw him and soon after X (when glow blue) to attack. That should drop him to about 25-30% health. After that repeat 1st sequence (double dash and attack from behind). From time to time he will charge at you so watch when he will glow yellow to parry and then attack. Don't rush and remember to dash on sides (left - right) as his attack got amazing range. Achievement will pop up right after fight.
This is my first guide so be gentle on me ;) if you have any suggestions let me know.