more muscular does not always mean stronger. Of course when you reach an elite level of competition size is not everything but it's relative. No 150lb twink can take out a angry and capable 220lb'er
155lbs Genki toyed and punished a 400lbs pro boxer Butterbean with ease.
One of my Trainers (166lbs) entered many open weight BJJ tournaments in
Brazil, he won most of them.
He defeated many 220lbs opponents and in the final he
submitted a skilled 260lbs opponent.