Machida, who was training with Munoz when he was tapped to replace an injured Michael Bisping, looked quick and confident in his new division. The former UFC light heavyweight champion patiently set up his striking attacks while staying clear of any potential Munoz takedowns.
After a feint to the legs to drop his opponent's guard, Machida rifled off a left high kick that was partially blocked but was still strong enough to send Munoz crashing to the floor. Machida followed to the floor but realized additional strikes were unnecessary and held back while referee Leon Hall stepped in to call off the fight at the 3:10 mark of the opening frame.
"It was very hard for me (to take the fight) because Mark is a good friend of mine," Machida said. "But you know, as a professional, I don't think about that and just do my job. But now that it's over, the friendship will continue."
With the win, Machida (20-4) established himself as an instant title contender at 185 pounds. Munoz (13-4) falls to 1-2 in his past three fights.
Machida also earned $50,000 for the "Knockout of the Night."
The night's co-feature was expected to deliver fireworks, but a controversial foul call resulted in a disappointing "no contest" result.
Sluggers Melvin Guillard and Ross Pearson engaged from the opening bell, both moving well and firing in quick punches.
When Pearson looked to explode into a flying knee, Guillard sidestepped the technique, leading to a scramble as he pushed an off-balance Pearson away. As Pearson scrambled up to his feet, Guillard blasted him with a pair of knees that opened up a huge gash on Pearson's forehead.
Referee Marc Goddard ruled the second blow an unintentional foul, claiming Pearson's hand was on the ground for the second knee, earning him the protection of a "downed" fighter.
Doctors ruled the cut severe enough to end the fight, and the bout was ruled a no contest.
English "Posterboy" Jimi Manuwa kept his professional record unblemished, albeit in bizarre fashion, as an apparent leg injury ended opponent Ryan Jimmo's night.
Manuwa, a striking specialist, struggled to find space to strike. Jimmo, a native of Saint John, N.B., kept the action tight and looked to work inside from the clinch. Manuwa was getting the better of the action, but the grinding work from Jimmo kept the pace low.
In the second round, Manuwa landed a solid knee as the two broke apart in the clinch, and as Jimmo stepped back to recover, his leg buckled, and he came crashing to the canvas. Unsure what was happening, Manuwa looked to pounce with punches, but referee Neil Hall recognized the injury and waved the fight off with 19 seconds left in the frame.
"The fight went how I thought it'd go," Manuwa said. "I knew he was a tough opponent. He's strong, but I had his number. It was just a matter of time before I caught him."
Manuwa remains (14-0) unbeaten, while Jimmo (18-3) falls to 1-2 in his past three appearances.
Norman Parke, the 26-year-old winner of "The Ultimate Fighter: The Smashes," moved to 3-0 in the UFC with a convincing decision win over a previously undefeated Jon Tuck.
Parke simply outworked his opponent from the opening bell, constantly moving forward and landing heavy left hands and rapid-fire combinations. While Tuck kept pace in the opening round, that changed over the course of the final 10 minutes, and the action was decidedly one-sided. In the end, Parke (19-2) outstruck Tuck (7-1) 154-76 according to a FightMetric report, and was awarded a unanimous-decision win with scores of 30-27, 29-28 and 29-28.
"It feels good, but I wanted the finish as people have said I'm winning on points," Parke said. "I felt good in there. I got in the groove, but I didn't want to overcommit myself. I was happy with my boxing performance, but next time I want the finish."
Swedish newcomer Nicholas Musoke made the most of his first UFC opportunity, scoring a slick submission win over longtime veteran Alessio Sakara.
Musoke and Sakara went toe-to-toe from the opening bell, firing punches in an entertaining slugfest. As they moved into a clinch, a Musoke trip takedown moved the action to the floor. Sakara alertly swept to the top, but Musoke spun his hips out and locked quick armbar, turning to his belly for additional torque and earning a verbal submission at the 3:07 mark of the first frame.
"It feels awesome; it's a dream come true," Musoke said after the win. "Being in the Octagon was special and it got to me a bit more than I thought it would. (UFC site coordinator) Burt Watson said a good thing to me yesterday — making it here is easier than staying here — and I want to prove I belong here."
Musoke (11-2-1), who replaced an injured Magnus Cedenblad on just two-weeks' notice, now boasts a six-fight overall win streak. Sakara (15-11) is now winless in four UFC outings.
In the night's first main-card matchup, top flyweight contender John Lineker outstruck grappling specialist Phil Harris en route to an impressive first-round win.
Harris was never able to bring the fight to the floor and was instead forced to box with the heavy-handed Lineker, who took full advantage of the opportunity. Lineker battered Harris with powerful hooks on the feet before finally dropping him with a thunderous left to the body that forced a TKO stoppage at the 2:51 mark of the opening frame.
"The fight went how I wanted it; I wanted to strike," Lineker said after the fight. "Everyone who steps in the Octagon is tough, and I just work my hardest to get the best results. We're going to sit down and see what's next, but I am looking forward to celebrating."
Lineker (23-6) owns four straight UFC wins, but his status as a title contender is questionable after he missed weight for Saturday's fight, marking the third time in five UFC appearances he's failed to hit the required mark. Harris (22-11) falls to 1-2 in the UFC.
Attendance was 10,355 for $1.5 million gate according to White.