Just 23, Mein is already a veteran. The former Strikeforce fighter showed it in the first round when he cooly escaped an armbar from Miller, a black belt in Brazilian jiu-jitsu, and got back to his feet where he had the advantage.
Mein (27-8) floored Miller (14-7-0 with one no contest) with a left to the chin with 90 seconds remaining in the round and bloodied him up before delivering a pair of punishing body shots to put him down again. He finished it off with more than a dozen blows at the fence before the referee stepped it.
"It was very close," Mein, who turned pro in 2006, said of the armbar. "I just kept rolling."
It was an impressive showing against Miller, a tough customer who came into the fight with a 6-5 record in the UFC — with 10 of those coming at middleweight. Miller had never been stopped before the fight, with his other losses coming by decision.
Fellow Canadian UFC fighters were quick to praise Mein's performance.
"Jordan Mein is a complete destroyer!" tweeted lightweight T.J. Grant.
"Mein is a force to be reckoned with," echoed lightweight Mark Bocek.
Mein has now won three straight and nine of his last 10.
The main event at the Bell Centre was a title fight between champion Georges St-Pierre and American Nick Diaz.
GSP was looking for his eighth straight successful title defence since winning his 170-pound championship back from Matt (The Terror) Serra at UFC 83 in April 2008. Only middleweight champion Anderson Silva has more title defences (10).
The crowd showed their feeling about the main event early on. They booed a display of Diaz's statistics on the video screens early in the evening, then cheered GSP's figures.
Canadians went 3-1 on the undercard.
Montreal's Patrick (The Predator) Cote won his debut at welterweight with a unanimous 29-28 decision that shocked (Vicious) Bobby Voelker and his camp. who thought they had the fight won.
More than few observers agreed with them.
Still it was a high-paced bout that had the Bell Centre rocking before the main card.
Cote (20-8) got plenty of love from the crowd, with the first Ole Ole rendition of the night in the first round. That was followed by chants of Cote Cote.
But in the cage, he was game but outgunned much of the time. Still he never stopped swinging and when he was put on his back, Cote attempted submissions.
"What a WAR!!!" tweeted UFC boss Dana White.
The home-town boy started strongly but the hard-hitting Voelker (24-9) got his attention with a couple of blows midway through the round. Then Voelker took him down and controlled him for the rest of the round.
Cote came out swinging in the second but Voelker weathered the storm and came back at him. Voelker went after Cote in the third, taking him down and hammering him on the ground.
Voelker was making his UFC debut after going 4-1 in Strikeforce
It's Cote's third weight class in the UFC. He went 5-7 as a middleweight and 0-1 as a late injury replacement against light-heavyweight Tito Ortiz way back at UFC 50 in 2004.
Montreal lightweight John (The Bull) Makdessi showed plenty of grit in fighting through the flash of Daron (Detroit Superstar) Cruickshank to win a unanimous 29-28 decision.
With both men having an array of flashy spinning moves, much was expected of this fight. There were some early boos as they felt each other out, but Cruickshank soon had Makdessi's lead leg red and inflamed from kicks.
Cruickshank had the better first round but Makdessi found his range and came back in the second. His nose bloodied, Makdessi (11-2) survived a poke to the eye in the third and continued to use his jab to score on the American.
It was Makdessi's second straight impressive win, following a decision over fellow Canadian Sam (Hands of Stone) Stout at UFC 154. For Cruickshank, it was his first loss in three UFC fights and he may want to rethink his tactics after seeing his six-fight win streak snapped.
"I think I can get much better." said Makdessi. "I want to improve everyday, and I know I can get right up there if I keep working hard."
Darren (The Damage) Elkins beat featherweight Antonio Carvalho of Ajax, Ont., via a first-round stoppage that had the fans booing and Carvalho wondering what happened.
Elkins (17-2) staggered Carvalho and then knocked him down, prompting Montreal referee Yves Lavigne to step in and wave an end to the fight at 3:06. Carvalho (15-6) was dazed but he was getting to his feet.
"Ya that was bad for Carvalho. He was rocked as on crazy legs but should have been given more time," tweeted White.
While some like White saw it as an early stoppage, Lavigne may well have saved Carvalho from further punishment.
"I feel bad for him, but of course I am going to say that I would have stopped him anyway," said Elkins.
"I don't blame Darren," said Carvalho. "He isn't the referee. Listen, he hit me with something because I remember going down. I shouldn't have been caught with the punch in the first place because some referees are safety-first and you don't get to do it again.
"I feel bad he got a big win and was booed. It wasn't his call to stop it like that.”
A former lightweight who move down a division, Elkins is the first UFC fighter to go 5-0 at 145 pounds.
Welterweight Rick (The Horror) Story (15-6) was too much for Quinn Mulhern, stopping the former Strikeforce fighter with a flurry of blows at 3:05 of the first round. Mulhern (18-3) was an injury replacement for Canadian Sean (The Punisher) Pierson and was outmatched.
Story, who had lost three of his last four after winning six straight, showed he deserves to move back up the billing on his next card.
"That felt great," he said. "I've been working hard to get back to where I was at and it felt great to win like that. I want to get back up and fight a big name next."
Bantamweight T.J. Dillashaw (8-1) caught Japan's Issei Tamura (7-4) with a kick to the face and then finished him off with a half-dozen nasty punches at the fence for a TKO 26 seconds into the second round. Dillashaw's third straight win left a dazed Tamura leaking blood.
"That was the best KO of my career — so far," said Dillashaw, runner-up to John Dodson on Season 14 of "The Ultimate Fighter."
"I knew he was out when I landed it. It was a great knee but he sort of head-butted my knee at the same time. I followed up just in case and he was out.
"My knee is killing me right now."
Lanky bantamweight George Roop (13-10-1), who had seven inches on his five-foot-six opponent, scored a unanimous decision over Reuben Duran (8-5-1). Roop, who has also fought at lightweight and featherweight, ended a two-fight losing streak.