Here is a real life example. My chick wrestled and is 9-0 undefeated at 130lbs. I have no formal fight training background but in about 15 years have been probably 40 or so street fights. Only lost a couple. Not being cocky at all I just get lucky.. not the point. Only stating that for experience value.
Anyways, me and my chick are getting pretty aggressive playing in the yard. I already know she can take me down even though I outweigh her by 80lbs (Fuckin single leg).. so I'm being pretty fucking close to how I am in a streetfight defensively. She shoots on me, grabs my leg, let's it go and gets my back. Shes wrapped around me like a monkey. Next thing I know I'm falling backwards caught in a standing rear naked unable to breathe, almost went out. Took her about 1 second from leg grab to choked out. Shit happens fast when your fighting someone that is trained. Even a girl. Lol.. I almost crushed her to death when we hit the ground. Point is, I think trained beats size and untrained experience more often than not. I've seen it quite a few times in my travels.