Two of the most successful fighters in UFC history square off this weekend in the main event of UFC 217 inside Madison Square Garden.
Defending middleweight champion Michael Bisping (30-7) holds the promotion's all-time wins record with 20. Georges St-Pierre (25-2) sits one shy of that mark and would surely hold the record had he not taken a four-year hiatus from the sport.
The former welterweight champion is back now, and moving up to middleweight for the first time in his UFC career.
Who leaves New York with the UFC's 185-pound title? ESPN asked some of the sport's top trainers for insight.
Duke Roufus, Roufusport
There's such a question mark about Georges at 185 pounds. It's one thing to train at a new weight class, but in a fight, you need to have the same endurance being a little heavier, and that's something you don't know until the fight.
The key for Bisping is to come out and set the tone, win the psychological warfare by beating him up early. That's always a key when someone has been out of the cage for a while.
And shut down the jab. Everything for Georges starts off the jab. Use your height, reach, parry, slip and rip -- every time the jab comes, have an answer to it. Obviously he can't overcommit and give Georges that single leg, but be aggressive.
I think the world of Georges, but I also think a very good bigger man always beats a great smaller man. Let's not forget, Michael started his career at 205 pounds, so you're talking, with newer weight-cutting techniques, a much bigger middleweight.
Din Thomas, American Top Team
If I were Mike, I would try to push the pace and get Georges to move backward. He's got to be dirty. Be mean. Georges is a nice guy, and he doesn't like it when people are mean to him. So Mike needs to fight as mean as possible. And that's one thing he can do. He's a mean fighter.
Carlos Condit is a mean fighter, and he had Georges looking away from him at times. That's the kind of thing Mike has to do. Carlos just didn't have the wrestling ability to deal with Georges. If he could have stopped a takedown, he would have been able to deal with him.
Georges is a super smart fighter, though, and I'm looking for him to win by decision or possibly submission. He's always been conservative. He won't take unnecessary chances. Bisping is durable and tenacious, but he doesn't have the fastest hands to keep Georges off of him.
John Crouch, MMA Lab
Michael is going to be bigger and he's not going to be intimidated by what Georges brings. It's a cool story about Georges coming back, but even at the end of his run, it was a struggle to finish or even really hurt people.
He would dominate anyway, but Bisping is the kind of fighter, when he feels that pressure, it turns into positive energy for him. I think Michael can pick him apart standing. He's a pretty fast middleweight.
Georges' game has always hinged on the dominant wrestling. If he's able to shoot a double and hold Bisping down, it's a different story. But personally, I don't think he'll be able to do that. He has always been good over five rounds, so to say he'll get finished is not giving him enough credit, but I think he'll be lumpy by the end of it.
Henri Hooft, HKickboxing
I think Bisping is going to be the better fighter. The fighting style of GSP -- we all know what he did before -- it's outdated. People are much better at defending the wrestling and his striking, for me, was never special. He did good stuff to get a takedown.
Bisping's coach has done really good work with him, and you can see they work together. As a trainer, you recognize what a fighter needs and for them to react to that in a fight -- and see it work -- there is nothing better for a trainer. And Bisping is a good student.
That's an advantage over a guy who is not really strong mentally. And GSP isn't. He wins the fight, but he's not very mentally strong. He's just more athletic than a lot of people.
That's just the way I see him. A couple times, I was in the locker room with him and he would say things like, 'I don't really want to fight at this moment.' He would joke about it. I was a fighter myself and I know how it is before a fight. Nobody really wants to fight right before a fight. But with him it was different, and I've kept that feeling about him.
Also, if you train with everybody in the world, that means you're not really confident in your own stuff. It doesn't make sense to train with 20 people -- boxing coach, gymnastics coach, kickboxing coach, karate coach, fitness coach. It's too much information. That's my opinion.
It's a fight. Anything can happen. I just think Bisping will outwork him. It will be a decision or a stoppage in later rounds.
Izzy Martinez, Izzy Style Wrestling
If Bisping wants to win, he can't be so scared of Georges' wrestling that it stops him from doing what he does best, which is put on pressure and throw strikes. And for GSP to win, he needs to take advantage of Bisping being aware of the takedown.
When I helped train Carlos Condit to fight GSP, we knew he was going to get in on our legs. You can't let that affect you mentally. We stressed to Carlos, 'Hey, when you do get taken down, don't make a fundamental error.' Make sure you're setting up a base to explode again. Try to land in a way where you're already working to get up.
You can't get disappointed by the hype. Kind of like Holly Holm with Ronda Rousey, too. You can't think, 'Don't get taken down, don't get taken down.' If all of a sudden you're on the floor, that can't be an, 'Oh, s---' moment.' You have to fight with less emotional investment.
Georges utilizes the jab and he has a very fundamental base. He knows exactly what he's looking for and his timing and range are perfect. Hopefully he comes out and performs well again. His wrestling really is one of the best in the world because of the timing and range.
Justin Buchholz, Team Alpha Male
I was GSP's biggest fan coming up. Why? Because he's the smartest guy in the cage.
It's possible we might see an even better GSP. He hasn't taken a day off. It's not just about technique. It's about speed, strength, coordination -- and he's been working on that, because he always knew he was coming back. And he cherry-picked his opponent.
Bisping is making a good case for why that was a bad idea, though. He's not a KO artist, but the guy is impressive. I can't say a single bad thing about Bisping. Much respect to him, but he's not icing guys with one shot. And I believe that's how you've got to take out GSP.
I think GSP has proven he's the best wrestler in MMA. We'll see if Bisping's camp can pick up on his timing, but he sets the tone for the whole fight in the first 30 seconds. Go back and re-watch his fights. He takes everyone down in the first 30 seconds.
Honestly, I don't believe strongly in ring rust. There are advantages and disadvantages to being away that long, but I think someone like GSP can go in there and get it done. I see the fight going to GSP.
Mark Henry, New Jersey striking
It's all on whether or not Georges can take him down. He always liked to shoot on that left side hip, so he takes down right-handed fighters a little easier than southpaws.
I think the weight difference is going to be pretty big. You heard Georges was ready to go as low as 155 pounds, all the way up to 185 pounds. I don't know how you could be able to go 55-to-85. I'm guessing he's on the smaller end of 85. And Bisping is a pretty big guy.
The one thing about Georges is he always prepares better than anyone else. I'm sure he's been training a long time for this, but it's a different mindset going into the Octagon in Madison Square Garden.
I hope he does well, but Bisping's wrestling defense has gotten better, Georges is smaller, and I think Bisping will keep it standing enough to win.
Trevor Wittman, Grudge MMA
The key for Bisping is he's got to keep his motion up. He's very fluid with his footwork and he's consistent. You see some of his last few fights, how close they were, and he performed. He weathered a storm against Anderson Silva and made good decisions in that storm.
The key for GSP is he's got to be fundamental. Don't change the game from what you used to do. He was starting to run into a stalemate near the end, but I think that was because he was so worn down from being the largest draw in the UFC.
Georges' time off will play a factor in this fight. I actually think you'll see him go through some trials and tribulations -- Bisping will have his spots -- but Georges will overcome them and control the later rounds to dictate how the fight goes. I have Georges by decision.
Duane Ludwig, Ludwig Martial Arts
There are a lot of X factors with GSP being out so long. When he had a layoff the last time, he came back and still looked really good, but not as good as before, and he mentioned that.
If anyone can prepare for that, it's GSP and Tristar. They know exactly what they're doing. What people don't realize is how good GSP's timing is. I've sparred with the guy quite a few times and he has excellent timing. It's what separates him.
I see an athlete, a gifted martial artist, who has excellent timing, going against an in-shape, 'won't take no for an answer' opponent in Bisping. St-Pierre will win a decision, but he's going to come out with some lumps and bruises, for sure.