Sean O'Connell had just left the cage following an exhilarating, come-from-behind victory over Dan Spohn. He had a little bit over an hour until he had to fight -- again -- in the semifinals of the Professional Fighters League's 2018 playoffs. The aim for O'Connell was to chill out and cool down. And then he bumped into "The Iceman."

"I ran into Chuck Liddell back there, backstage," O'Connell said. "I don't know why he was even there. I'm riding this high, I just won in kind of a weird comeback fashion. ... I was like, 'Hey man, I'm a big fan, thanks for being here.' Or whatever. He was like, 'Yeah, yeah, yeah.' Shook my hand, and that was it."

That kind of unexpected encounter, with one of the most popular fighters in MMA history, could throw someone off their game. But O'Connell brushed it aside, sat down in a chair in the bowels of Southern California's Long Beach Arena, grabbed some Gatorade and tried to relax.

Traveling uncharted waters

There was no modern blueprint for O'Connell's situation in the first PFL playoffs. After beating Spohn by majority decision in a two-round PFL light heavyweight quarterfinal, he was heading into a three-round semifinal bout with Smealinho Rama on the very same night.

The PFL has brought the concept of fighting multiple times in one night -- once a staple during MMA's early days -- back into the MMA mainstream as part of its traditional sports-like format. After a regular season consisting of two bouts for each fighter, beginning in May, the top eight fighters (or four, in the case of women's lightweight) are seeded in a bracket.

Then, during three weeks of PFL playoff action (starting on Oct. 11), they have to fight both their quarterfinals and semifinals bouts on the same night. Finally, on New Year's Eve, the championship fight in each division is held with $1 million on the line.

Surviving the grind

Sean O'Connell beat Dan Spohn by majority decision in the PFL light heavyweight quarterfinals, and then had to get ready for a second fight on the same night. PFL/Ryan Loco

The entire year is a bit of a meat grinder for fighters who make it all the way to the finals, like O'Connell did. He knocked out Rama in the semifinals, then stopped Vinny Magalhaes by third-round TKO on Dec. 31 to win the seven-figure payday.

O'Connell took his $1 million and retired, but remained near the PFL cage as the play-by-play announcer for the 2019 season.

O'Connell said the mental preparation, especially for fighting twice in one night, is of the utmost importance for the athletes.

"You start planning how you're gonna spend the damn money once you make the playoffs," O'Connell said. "But you've gotta be mentally prepared to flip the switch, get a win, turn it back off, flip the switch again, get another win and do it all in one night.

"And that's not something that any of us have had to do before, and I think that's where the big mental hurdle comes in."

O'Connell, 36, had a secret weapon. His coach is Jeremy Horn, who has more than 110 pro fights and began his career in 1996 when fighting multiple times in a single night was the norm.

The UFC started in 1993 with an eight-man, one-night tournament and continued to use that format through most of the 1990s. Many regional circuit events borrowed from that format as well.

One-night tournaments are exceedingly rare in the modern, highly regulated era of mixed martial arts, though, and the UFC hasn't held a one-night tournament since November 1999, at UFC 23.

Staying loose

Lance Palmer was able to stay loose after defeating Max Coga in the PFL featherweight quarterfinals and defeated Andre Harrison in the semifinals later than night. He'd ultimately go on to win the featherweight title and $1 million. PFL/Ryan Loco

Before his second fight of the night, Horn told O'Connell that it didn't matter who he was fighting next -- Rama or No. 2 seed Maxim Grishin. He had to go into the back, calm down and rehydrate with electrolytes until his heart rate was at a normal, resting pace. Then, about 45 minutes prior to the semifinal, O'Connell could start warming up again.

O'Connell made the most of the opportunity. So did Lance Palmer who won the PFL featherweight season last year and is looking to repeat in 2019. Palmer is the top seed at featherweight this season, and he fights Gadzhi Rabadanov in the featherweight quarterfinals on Oct. 17 in Las Vegas.

Palmer said his key to preparation is mixing up sparring partners during training. He'll spar for five rounds, but new partners will come in and out, all with unique attributes. That simulates the uncertainty of whom Palmer might fight in the semifinals.

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"I think having that and having to adapt during those rounds in sparring to a different partner or somebody who's fresh, I think that helps a lot with being able to fight two separate people in one night and different styles," Palmer said.

The last two years have been a whirlwind for Palmer. He's had six fights in the last 16 months, and if Palmer makes the 2019 finals, it'll make nine fights in 18 months.

Despite the volume, Palmer has embraced PFL's structure. Of course, $1 million at the end of the year doesn't hurt, either.

"I enjoy it, because there's nothing else like it and it's something like, how can I figure out this system and how can I be the best at this format?" Palmer said. "I feel like last year I did a pretty good job of it, even though I didn't get finishes. I feel like this year I can have it figured out to the point where I can get finishes in these fights.

One long journey

For Vinny Magalhaes, who won both of his fights on night one of the PFL light heavyweight playoffs in 2018, preparation was a matter of never scaling back his training throughout the season. He's done the same during his second run in the PFL. PFL/Ryan Loco

Magalhaes, who lost to O'Connell in the light heavyweight final last year, has stayed in the gym since the start of PFL's first season, and he views those long stretches as one big training camp. He said after winning in the quarterfinals and semifinals in 2018, he was back in the gym two days after the card. Magalhaes, 35, will face Rashid Yusupov in the light heavyweight quarterfinals on Oct. 31.

"I was trying not to get myself to have to try to get back into shape," Magalhaes said. "I'm [35] now. It's completely different than when I was 23, 24. I could take time off and in three weeks I would be back in shape. Now, two or three weeks off or even one week off, it takes me almost a whole month to get back in shape no matter how hard I train."

Magalhaes said two fights in one night wasn't the most foreign concept for him, especially as a multiple-time champion in Brazilian jiu-jitsu tournaments. While there was some worry of injury after the first bout, Magalhaes came out unscathed with a first-round submission win over Rakim Cleveland.

"That was nothing new for me," Magalhaes said of competing twice in one night. "But fighting, of course there's always that thing that you don't know how you're gonna come out of the first fight, if there's a cut, a bruise, a broken bone, whatever it is. You always have those small concerns. Since I came out fresh from the first fight last year, the second fight mentally was so much easier. Because I knew that day I was ready to perform."

A second chance after a tough break

John Howard defeated Eddie Gordon to advance to the PFL middleweight semifinals in 2018, but an illegal knee cut Howard's path to the finals short. PFL/Ryan Loco

It doesn't always work out according to plan, though. John Howard was lined up for success in the 2018 PFL playoffs after he won his quarterfinal fight in the middleweight bracket against Eddie Gordon. His semifinal bout later that night, against Louis Taylor, saw Howard eliminated because of unlucky circumstances.

An unintentional illegal knee by Taylor in the second round brought the fight to a premature end as a draw. Because Taylor won on the scorecards in the first round, he advanced to the finals over Howard. Under the new rules for 2019, the decision for who would advance in a draw would fall to the judges.

Still, that experience will come in handy for Howard as he enters his second PFL playoffs, this time in the welterweight division. He fights David Michaud on Oct. 11.

"After that first victory, your adrenaline is on a thousand. I was a little sore, but my adrenaline was pumping," recalled Howard. "The most important thing was to calm down and recover. I didn't even have to warm up. You're so ready. It's such a rush, I was like, 'Warm up? I'm ready to go.' You just want to save your energy for another three rounds."

Final words of wisdom

Going into this year's playoffs, O'Connell said he'd advise the competitors to simulate two fights in one night in the gym. Rather than doing just one session of hard sparring, try doing it twice in the same day with some space in between. Since fighters today are not used to competing twice in a single night, O'Connell believes that's the best way to get the body and mind used to it.

"This format is unfamiliar to all of us in the younger generation of fighting," O'Connell said. ... "All the guys in my generation of fighting, we've never done it before. And now you're being asked to do it on the highest stage that you're getting to, the biggest opportunity that you've had in your career, potentially a million dollars within two or three fights. At that point, you can taste it -- you can touch it."