UFC 43: Couture v Liddell
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This Saturday at UFC 252, UFC heavyweight champion Stipe Miocic and Daniel Cormier will throw down for a third and final time. With their series of fights split at one knockout win for each man, the fight is not only about their individual legacies and the status of "greatest heavyweight in UFC history," but also about claiming victory in one of the biggest rivalries in UFC history.

Trilogies represent the best case for a fighter to claim true superiority over a rival. A single loss can be chalked up to a bad night, a fluke result or bad judging. But getting the better of a trilogy means there is no doubt over who the better fighter was.

There have been some truly classic trilogies in UFC history, featuring some of the most iconic names in the the sport. Let's take a look at three of the best before Miocic and Cormier throw down in the UFC APEX in Las Vegas this weekend.

Chuck Liddell vs. Randy Couture: Couture's move to light heavyweight after losing back-to-back fights -- which also ended his second reign as UFC heavyweight champion -- seemed like a big risk. He was always an undersized heavyweight and now moving down in weight to take on Liddell, who was operating as an absolute killer on a 10-fight winning streak and more than deserving of a shot at light heavyweight champion Tito Ortiz. Liddell was becoming the UFC's biggest star and Ortiz was showing the appearance of a man who was ducking the top contender to his title. The UFC booked Couture vs. Liddell for the interim belt, a move that was, by all appearances, going to set up a unification bout between Liddell and Ortiz. But Couture became one of the biggest monkey wrenches in UFC history when he dominated Liddell before scoring a TKO in the third round of their meeting at UFC 43 in June 2003.

Couture went on to take out Ortiz at UFC 44 in September of the same year, and after a two-fight series with Vitor Belfort that completed a different, less glamorous, trilogy, found himself back in the Octagon with Liddell. At UFC 52 in April 2005, the killer version of Liddell returned as he scored a clean, first-round knockout just over two minutes after the opening bell to capture the light heavyweight championship. Liddell repeated the feat the following February, scoring a knockout early in the second round and sending Couture into a retirement that lasted just over a year -- until he returned and won the heavyweight championship for a third time. Liddell, meanwhile, went 3-6 after the completion of the Couture trilogy, ending his legendary career with a whimper.

Georges St-Pierre vs. Matt Hughes: St-Pierre blazed into a shot at the vacant welterweight championship against Matt Hughes looking like the future of the sport. At 7-0, St-Pierre's resume was far shorter than Hughes, who entered their UFC 50 fight in October 2004 with a 36-4 record and with one lengthy title reign already in his back pocket. Hughes was two fights removed from his welterweight championship reign ending at the hands of BJ Penn but was 14-1 in his 15 most recent fights and had been in as many UFC championship fights as St-Pierre had total career fights. The fight was one round of solid action with both men showing off their best qualities before Hughes' veteran savvy allowed him to lock up an armbar and secure the tap one second before the end of the opening round.

Before the two would meet again, Hughes would rattle off four consecutive wins, including avenging the loss to Penn, while St-Pierre picked up five victories, including his own win over Penn. At UFC 65, St-Pierre got his shot at redemption and made the most of it, stopping Hughes with a head kick followed by vicious ground and pound in the second round to win the welterweight championship. The rematch made it clear St-Pierre had passed Hughes in skills and by a wide margin. That was only made more clear when Hughes and St-Pierre battled for a third time at UFC 79, finishing Hughes with an armbar, the same move Hughes used to win their first battle. That fight won St-Pierre the interim welterweight title, having lost the title to Matt Serra in a massive upset. At UFC 79, it was actually supposed to be Hughes getting a title shot at Serra when Serra pulled out, opening the door for the trilogy fight for the interim belt, which St-Pierre would unify by beating Serra in their UFC 83 rematch.

Frankie Edgar vs. BJ Penn: Coming into UFC 112 in April 2010, Edgar was a big underdog to Penn despite a 12-1 record. Penn was, after all, considered the greatest lightweight in UFC history and had tore through Joe Stevenson, Sean Sherk, Kenny Florian and Diego Sanchez during his run with the championship. Edgar and Penn would go nip-and-tuck for five rounds in their first meeting before Edgar took a decision victory in one of the biggest championship upsets in UFC history. The decision was controversial, however, with the majority of media outlets scoring the fight for Penn and one judge turning in a bizarre 50-45 card in favor of Edgar.

While the odds weren't as wide as the first meeting, the August 2010 rematch saw Penn again enter the Octagon as a solid favorite, with the common line of thinking being that Penn deserved the first decision and would be motivated to reclaim the belt and remove judges from the equation. Instead, Edgar put on a dominant performance, winning in the grappling, wrestling and striking arenas across all five rounds to take a clear decision and cement his status as the true champion at 155 pounds. It would be nearly four years before they completed the trilogy, battling after both men served as coaches on The Ultimate Fighter. This time at featherweight, it was Edgar coming in as the favorite, and he left no doubt he was the better man by scoring a knockout in the second round of a lopsided contest that was part of Penn's eight-fight winless streak to end his career.