St. Pierre would get his wish if Diaz defeated Carlos Condit at UFC 143 during an interim welterweight bout Saturday night in Las Vegas.
Diaz tried to make St. Pierre's wish come true, but Condit had other plans.
Condit used elusive footwork and counter-striking to earn a unanimous decision over Diaz. The judges scored the fight 48-47, 49-46 and 49-46.
ESPN.com had Condit winning the fight by a score of 48-47.
"It's pretty surreal," Condit said after the interim 170-pound title belt was placed around his waist. "In my previous fights, I've kind of come on strong in the later rounds and found my rhythm."
Diaz started strong in the first two rounds. But Condit began to find his rhythm by Round 3.
He relied heavily on his footwork to avoid the stalking Diaz. But unlike in the first two rounds, Condit was able to connect more with kicks and counter-punching. He also landed a hard elbow in the third round.
From that point on, Diaz found it difficult to land punches in bunches. But the former Strikeforce champion never stopped putting pressure on Condit.
In the final round, Diaz was able to get Condit on the ground, and attempted to finish the fight with a rear-naked choke and arm-bar. But Condit survived.
The loss was difficult for Diaz to swallow. He announced he would no longer compete in MMA.
"I'm not going to accept the fact that this was a loss," Diaz said after falling to 26-8 with one no contest. "I pushed him back the whole fight; I took him down. I think I'm done with this MMA. It's been a good time.
"I don't need this. I pushed this guy the whole fight. I landed the harder punches. He kicked me a few times."
Condit (28-5) now will set his attention on facing St. Pierre, who is recovering from a torn ACL in his right knee.
St. Pierre expects to begin full training in June. He hopes to fight in November.
Improved Werdum defeats tough Nelson
More than three years have gone by since that loss, and Werdum -- who took his skills to Strikeforce -- is a different fighter today. He showed just how much he has improved against Roy Nelson.
Werdum used his superior reach to hit Nelson repeatedly with hard right hands and kicks. He also landed numerous knees when the fighters were in the clinch.
Those knees left Nelson's face a bloody mess. But Nelson never took a backward step and landed a few hard overhand rights that caught Werdum's attention on more than one occasion.
In the end, however, Werdum's improved striking gave him the edge in each round, and he came away with a 30-27 win on all three of the judges' cards.
ESPN.com also had Werdum winning 30-27.
Despite his lopsided win, Werdum (15-5-1) praised Nelson's effort.
"I know Roy Nelson is a tough guy, but I train every day on my knees," Werdum said. "He didn't hurt me, but he punches hard."
Nelson has now lost three of four. He falls to 16-7 overall.
Pierce earns Koscheck's respect in split loss
Pierce, however, called Koscheck out, and the welterweight contender had little choice but to accept.
After three rounds of action, Koscheck defeated Pierce, but he will no longer say they are not in the same league.
Koscheck earned a split decision, but the outcome easily could have gone to Pierce, who landed several hard right hands throughout the bout. However, Koscheck was able to take Pierce down twice in the fight.
Two judges had Koscheck winning 29-28. The third had Pierce winning 29-28, as did ESPN.com.
Many in crowd also felt Pierce deserved to get the win, but they always want Koscheck to come out on the losing end.
"You guys boo me all the time," Koscheck said to the fans inside Mandalay Bay Events Center, where he improved to 17-5. "Deal with it. I find a way to win.
"Mike Pierce is a tough guy. I knew this coming into the fight."
Pierce slips to 13-5.
Barao stands tall against Jorgensen
Renan Barao is one of the best bantamweights in UFC, but some question whether he'd have difficulty against a highly skilled wrestler.
Scott Jorgensen was expected to answer that question. But he did not.
Throughout the fight, Jorgensen opted to stand with Barao, and he paid the price. Barao repeatedly hit Jorgensen with left-right combinations and connected with several hard kicks to earn a 30-27 score from each of the three judges.
ESPN.com also had Barao winning 30-27.
"He was a very tough opponent," said Barao, who improved to 28-1with one no contest. "I expected that. Now I want the [135-pound] belt."
Jorgensen has his two-fight win streak snapped. He is 13-5 overall.
Herman doesn't lose focus, submits Starks
That experience edge served Herman well as he overcame several right hands from Starks in the first round to pull off a second-round submission win.
Starks, a wrestler making his second appearance in UFC, surprised Herman in the first round by landing several hard right hands. The punches would leave Herman's left eye swollen heading into the second.
But the damaged left eye wasn't severe enough to prevent Herman (20-7) from taking Starks to the ground and getting his back. Once in the dominant position, Herman applied a rear-naked choke that forced Starks to tap at 1:43.
"He was landing some good right hands. Good thing I have a good chin," Herman said. "I was surprised I was getting hit by him. But I pulled it off."
Starks loses for the first time as a pro, falling to 8-1.
Well-rounded Poirier takes Holloway down
For a few minutes of the opening round, Max Holloway was giving featherweight contender Dustin Poirier all he could handle in the standup.
But Poirier is a solid fighter standing or on the ground. And it was on the ground where he had a huge advantage over Holloway
Poirier got positioning on the ground and applied a triangle-armbar submission hold that forced Holloway to tap at 3:23 of the first round.
"I came here to get a win. I'm 4-0 in UFC. I'm here to become a champion," said Poirier, who improved to 12-1 overall. "He's tough. He's a tough kickboxer. I took him very seriously."
Holloway, who fought for the first time in UFC, suffers his first setback as a pro. He is now 4-1.
Low kicks cost Caceres dearly
But Caceres' effort was erased by kicks to the groin that sent Figueroa to the ground in pain. The second low kick forced referee Herb Dean to deduct two points from Caceres.
Losing those two points would determine the outcome of this fight, as Figueroa walked away with a split decision win.
Two judges scored the fight for Figueroa 28-27, while the third saw it for Caceres 28-27. ESPN.com gave Caceres the edge 28-27.
Figueroa is now 9-1.
Caceres drops to 6-5. He is 1-3 in UFC.
Brown regains his touch with KO of Cope
Matt Brown has struggled to find his rhythm in recent fights. Having lost four of his five most recent bouts, Brown was in dire need of a win against fellow welterweight Chris Cope.
He got that much-needed victory with a second-round knockout of Cope.
Brown finished Cope at the 1:19 mark with a left hook. He set up the finishing touch with a right hand that stunned Cope.
"I got away from who I am," Brown said after improving to 13-11. "I'm back."
Cope has now lost two fights in a row. His professional record slips to 5-3.
Riddle rallies to edge Martinez
Henry Martinez is a natural lightweight, but when UFC offered him a welterweight fight against Matthew Riddle, he quickly accepted.
Two weeks after agreeing to this welterweight showdown, Martinez nearly pulled off a huge upset.
After an impressive opening round, in which he got the better of the striking exchanges, Martinez began running out of gas in Round 2 against the bigger Riddle.
As Martinez slowed down, Riddle picked up his offense to come away with a hard-fought split decision.
Two judges scored the fight 29-28 for Riddle. The third gave the edge to Martinez 29-28. ESPN.com gave it to Riddle 29-28.
Riddle ended a two-fight skid to improve to 6-3. Martinez, who fought for the first time in UFC, slips to 8-2.
Experienced Natal defeats newcomer Kuiper
Michael Kuiper entered his UFC debut unbeaten as a mixed martial artist. But he had never faced anyone as good as veteran Rafael Natal.
The gap in quality of opposition would play a major role in this middleweight bout. Natal won the first two rounds -- utilizing his takedown skills in the first and relentless striking in the second -- and survived an early knockdown in the third to earn a unanimous decision.
All three judges scored the bout for Natal -- 30-27, 30-27 and 29-28. ESPN.com had Natal winning 30-27.
Kuiper falls to 11-1. Natal improves to 14-3-1.
Thompson registers KO in UFC debut
Welterweight Stephen Thompson made his debut inside the Octagon memorable with a first-round knockout of Dan Stittgen in the UFC 143 opening bout.
Thompson (6-0) controlled the action from the start by using kicks to keep Stittgen (7-2) from mounting any offense. He then delivered a right kick that landed on the side of Stittgen's head.
Stittgen, who was also making his UFC debut, never saw the kick. He fell to the canvas at 4:13 and couldn't manage to get up.
Franklin McNeil covers MMA and boxing for ESPN.com. He also appears regularly on "MMA Live." Follow him on Twitter at http://twitter.com/Franklin_McNeil.