"Winfighting": How Williams beat the bigger, stronger man on the inside. A lot to talk about here, so let's start off with the sequence that led to Hurd being knocked down.
You'll notice in the first slowdown (0:04), after dodging a salvo from Hurd, Williams comes in to tie Hurd up. Hurd, no stranger to an infight, attempts to wrestle and get his arms on the inside. Watch Williams' head movement here, it'll be important later.
By taking his head off the centre-line he reduces Hurd's ability to catch him with a short-uppercut on the inside, as he did before (although it was parried (0:10)). However, it also grants Williams vision. At 0:18-0:28, look at where Hurd's eyes are - buried into Williams' neck.
Conversely, Williams is able to see a lot more. Particularly, where Hurd's hands are, and his shoulder. From the initial shoulder movement, and his ring IQ, Williams anticipates Hurd to throw the left uppercut. Thus, he uses his shoulder to create distance (0:31).
This action is two fold in its brilliance. Firstly, it neuters the effectiveness of Hurd's uppercut, which glances off (0:34). More importantly, it allows Williams to load up on his right hand, slingshotting it into Hurd as he pulls his left shoulder back.
He immediately follows up with his own short uppercut on the inside - again, anticipating Hurd's action. Jolly good shot this.
However, it isn't always possible to use one's shoulder to create space, especially against a big, strong, skilled boxer like Hurd. Here, Williams does the opposite. At 0:02, he creates space through the smallest of backsteps. Hurd manages to block the left, but the right lands.
Further, on the note of physicality, this again shows how Williams can circumvent the strength difference between the two through guile. Try it yourself - hold one arm in a similar position as Williams has his left at 0:10. Then, with your other free hand, try move that forearm.
You'll find it very difficult indeed. It's a very, very solid position for the arm to be in mechanically. Further, Williams is able to use it to obfuscate Hurd's view, and sneak a right hand through.
Early on, Williams has a lot of success with his own short uppercut on the inside. We can assume here that Williams has his left hand on Hurd's right, from how he ties Hurd up (0:05) after landing the uppercut (0:04). This is a trick Durán often used, too.
Also note how little space Williams needs to land that uppercut! The two were practically touching! Again, watch Williams' head movement here. With it, he shifts from defence to offence, catching Hurd with a big left hook at 0:10 as he moves his head off the centre line.
This same hand placement appears again, only this time used to neutralise Hurd's offence. After landing the hook at 0:02, instead of returning to a high guard Williams leans his hand on Hurd's right, and slips in to tie Hurd up after the latter tries to land a couple of his own.
Further, as Hurd wrestles for positioning, Williams' superior hand placement allows him to slip in a rear uppercut to the body (0:13).
That's about all I'm prepared to do today, as this already ended up way longer than I expected, from only 50-odd seconds of footage! Golly! If anyone else has things they'd like to add, feel free. I hope you enjoyed!