Hendricks will need confidence, patience, discipline, intelligence, offensive and defensive grappling, stamina, feints, level changes, head movement, footwork and, maybe, some luck for good measure. A little luck never hurt anybody in a UFC title fight.
That left hand, though -- the reason you hear so much about it is because even though Hendricks (15-1) must take every tool he has into the Octagon against St-Pierre, at any moment that one left hand might be all it takes.
What is it about that left hand that makes it so dangerous and gives us reason to believe Hendricks could become just the third man to ever defeat St-Pierre (24-2), and first since 2007?
ESPN.com asked that question of Hendricks, as well as St-Pierre and five previous Hendricks opponents with firsthand knowledge of that stinging left.
Hendricks: "Realistically, [the power] comes from my legs and my butt. I walk around at 225. I have big legs and a big butt. That's where all the power comes from. And, you know, wrestling -- always being in that stance and ready to explode."
Handling Hendricks' power
T.J. Grant (lost to Hendricks via majority decision at UFC 113 in May 2010): "The thing is, he doesn't have to try to throw for power -- he just has it. He has always got his legs involved in every punch, too. That's when you murder guys, when you have your feet and hips involved in every punch. That's why Johny has so much power is all his life in wrestling. When he throws that big Popeye forearm at your head, you're going to go down."
St-Pierre: "His left is his signature move but he works on many things. He's a very complete fighter. He's probably one of the best in the division in knockout power and the reason why is he's so good you don't see it coming. The way he throws it, I believe you don't see it coming."
Martin Kampmann (lost to Hendricks via knockout at UFC 154 in November 2012): "I think the problem was I was preparing too much for the left hook and then he came straight with one. The one he got [Jon] Fitch with, he was throwing it wide, wide. With me, he came straight down the middle."
Rick Story (defeated Hendricks via unanimous decision at TUF 12 Finale in December 2010): "During the fight, when he was punching me, I thought, 'Eh, this is nothing I haven't felt before.' He's placing them. His punching power isn't seriously superior. To be able to place them you have to throw them and some people hesitate. He has got confidence in it now so he's throwing a lot more."
Josh Koscheck (lost to Hendricks via split decision at UFC on Fox in May 2012): "For me, it was no big deal. I like fighting southpaws. I prefer it. They are better for my style. When he throws the left, I throw the right. I think he has definitely got power in his hands because he has knocked out a lot of guys and the ones he hasn't have felt it because they've been knocked down, but for me it was no big deal."
Mike Pierce (lost to Hendricks via split decision at UFC 133 in August 2011): "It wasn't his straight left hand that caught me off guard. His left uppercut is kind of funky and then his coach [Marc Laimon] yelling, 'Cheeseburger, cheeseburger!' code names for combinations. He hits pretty hard but not the hardest. I got thumped pretty hard by Aaron Simpson, that was probably the hardest I've ever been hit."
Story: "The main concern going into the fight was he knew he was heavy-handed, but the thing is, with all his previous fights, he was always pushing forward. My coach, Pat White, told me, 'If you get him going backward, he's not going to have any power on his punches.' That was my biggest focus."
Koscheck: "The game plan for Johny was to mix it up on the feet. You can hear [trainer] Bob Cook in the corner, it's crazy, he's always saying, 'Get off first! Be first!' That was pretty much our game plan -- get off first, get on him. With Hendricks, it's much easier to get off first and then get away from the big left hand."
Grant: "He has got timing. He puts his whole body behind his punches. He is accurate but a lot of times he also level changes with his head and hips and that kind of brings the guys' hands down. He 100 percent commits. He's a confident fighter. When you're confident, you don't hesitate and those milliseconds of hesitation are the difference between knocking a guy out or taking him down."
Story: "What's important for Georges is to stay out of Johny's range. What's important for Johny is to get into Georges' range. He's going to have to mix it up and get pretty creative. Georges has been doing this a long time."
Hendricks: "Whenever you're wrestling in college, you've got to do all these setups and your reaction from [outside of an opponent to inside] has to penetrate through all these distractions and get to the legs very quickly and explosively. That's what has really helped me out [in fighting]. They try to keep me at bay because I'm so short, but I use that explosiveness to close the distance."
Kampmann: "If Johny catches him on the button he'll hurt him, but St-Pierre is going to fight him smart. He's going to try to jab him from the outside the whole fight. Johny is good at closing the distance but he's going to get jabbed the whole fight. If Johny commits hard, that's how I think St-Pierre will take him down. Even though Johny is the better wrestler, I think St-Pierre can still take him down. That's how I think St-Pierre is going to fight him, but sometimes s--- don't go to plan."
Koscheck: "Johny Hendricks is a tough young fighter and I wish him the best but I think St-Pierre will outpoint him. Georges is smart. He's a game planner. He'll jab, use his wrestling at times, keep Johny at a distance and get off first. Georges is a lot faster than Johny. He'll end up winning a decision."
Pierce: "I'm definitely going for Johny Hendricks. I want to see him knock Georges St-Pierre out. In his past several fights Johny has really excelled at catching guys. St-Pierre has shown in the past he doesn't have the best chin in the world. We all saw him fall to Matt Serra and I think Hendricks has all the capabilities to do the same sort of thing and even more so."
Grant: "You can never count Georges out of any fight, but I think this is probably the most dangerous fighter he has fought just because Johny has that great wrestling pedigree. Unlike Koscheck, I feel like he's really good at making the knockout happen, whereas Koscheck wings a lot of right hands and if it doesn't land, he doesn't always have the second and third option -- I think Johny does. I give the advantage to Johny, personally."
Hendricks: "Whenever you get a guy that walks in at 190 to 195 pounds -- that's usually what I walk into the Octagon at -- and you get that moving pretty quick, he can throw a 50 percent punch and lay somebody out. It's about accuracy. You touch that jawline and anybody is going night-night."