10. BJ Penn over Matt Hughes, UFC 46, Jan. 31, 2004 -- Las Vegas
Hughes was the prototypical UFC powerhouse in the early 2000’s. Using brute strength and vicious ground and pound, no one could compete at welterweight against Hughes that was until a former 155er stepped up to face the growing legend. Penn proved superior technique and jiu-jitsu could counteract brute strength and takedowns. Hughes streak of five straight title defenses (Gil Castillo, Carlos Newton, Hayato Sakurai, Sean Sherk, and Frank Trigg) and 13 straight wins was snapped when Penn got his back and locked on a rear-naked choke.

9. Nick Diaz over. Takanori Gomi, PRIDE 33 Second Coming, Feb. 24, 2007
It was eventually ruled a no-contest because shockingly Diaz tested positive for marijuana. We’re not a commission so the win counts in our books. Diaz was allowed to walk away from the UFC after several close losses and was taking on Gomi, who had won 13-of-14 fights. Diaz pushed the pace and peppered Gomi’s face with punches. He also walked through some big shots and suffered a nasty cut. Gomi went down from exhaustion where got locked up in a gogoplata for the finish.

8. Brett Rogers over Andrei Arlovski, Strikeforce, June 6, 2009 -- St. Louis
Sure Arlovski was coming off a loss to Fedor Emelianenko but he had fought his fellow Russian competitively. Rogers was simply a tune-up to get back on Fedor’s radar. The soft-looking Rogers wasn’t even a full-time MMA fighter splitting his time between training and changing tires at Sam’s Club. At 6-foot-5, 265 pounds, Rogers can punch and Arlovski, a former UFC heavyweight, found it out quickly. The Russian was dropped and now his career is in shambles.

7. Randy Couture over Tim Sylvia, UFC 68, March 3, 2007 -- Columbus
Couture had sailed off into the sunset. He could compete no longer at age 44 and that was down at 205 pounds. Then he tried the unthinkable, a heavyweight title challenge against 6-foot-8, 265-pound Tim Sylvia. Couture got the crowd to explode when he knocked down Sylvia in the opening minute of the fight. He schooled Sylvia rest of the way. He punched Sylvia when the big man expected a takedown and took him down when he expected to get punched. It was a masterful performance and another big upset for
Couture.

6. Houston Alexander vs. Keith Jardine, UFC 71, May 26, 2007 -- Las Vegas
Alexander, a little known slugger from Nebraska, was nearly denied a license to fight someone at Jardine’s level. Jardine either overlooked him or had a lack of respect for Alexander’s power. Once he was being lifted off his feet by Alexander uppercuts and knees, it was too late for Jardine, who lasted just 48 seconds.

5. Joe Warren over “Kid” Yamamoto, DREAM 9, May 26, 2009 -- Yokohama, Japan
You’ll notice there aren’t too many fights in Japan listed. That’s because the matchmaking in Japan tended to make sure the big stars face plenty of outsized or inexperienced opponents. Warren, a Olympic level Greco-Roman wrestler, was a prime example. With one MMA fight under his belt, he took on the 135-pound Japanese legend Yamamoto. Warren took it to Yamamoto outwrestling him throughout and walking through several huge punches from one of the best knockout fighters in MMA history. Even the judges in Japan couldn’t deny that Warren pulled off a massive upset.

4. Joe Lauzon over Jens Pulver, UFC 63, Sept. 23, 2006 -- Los Angeles
“Lil Evil” was back after four year away! Pulver, one of the original little men to win a title in the UFC, was welcomed home as the promotion was reintroducing its new 155-pound weight division. Pulver, a favorite to take the title, was given an “easy” fight against an unknown 22-year-old, nerdy looking kid from the Boston area. Lauzon, now know for his submission game drilled Pulver with left hook that spelled the beginning of the end. Lauzon delivered as a minus-650 dog in just 47 seconds.

3. Gabriel Gonzaga over Mirko "Cro Cop" Filipovic, UFC 70, April 21, 2007 -- Manchester, England
American fans of PRIDE had been waiting for the day Cro Cop would come to the states and destroy the UFC’s heavyweight division. Dana White failed to land Fedor Emelianenko but Cro Cop was a close second. Filipovic opened with a win over Eddie Sanchez and was expected to crush Gonzaga. How could Gonzaga avoid Cro Cop’s lethal head kick? By delivering one of his own. Gonzaga nailed Cro Cop with a left kick to the head. Cro Cop crumbled to the mat and fell oddly with his leg pinned beneath his limp body. How he didn’t tear his knee is still a mystery. Cro Cop has never recovered from that loss nor have bettors if they layed the minus-680 odds on the Croatian.

2. Matt Serra over Georges St. Pierre, UFC 69, April 7, 2007 -- Houston
Serra was a solid 155 pounder in his day but he seemed content to teach at his schools on Long Island and was done as an active fighter until he was invited “The Ultimate Fighter” where he beat Chris Lytle in the title fight to earn a shot against the sport’s next big star, GSP. The 5-foot-6 Serra shocked the world as an 8-to-1 underdog when he clipped St. Pierre with a huge right to the top of his head. GSP never recovered giving Serra the UFC welterweight title at 32 years old.

1. Forrest Griffin over Mauricio “Shogun” Rua, UFC 76, Sept. 22, 2007 -- Anaheim, Calif.
No one believed “The Ultimate Fighter” would actually produce a UFC champion. This fight began Griffin’s path to the light heavyweight title. His win over Quinton Jackson was a big upset but this was bigger. Rua was arguably the biggest addition from the UFC’s acquisition of PRIDE. He was ranked by many as the top 205er in the world and it was just a matter of time before he took over the division from Jackson, who he had destroyed two years earlier. Griffin is known for his crazy cardio and size, and it played out big time in Southern California. Shogun overlooked him, wasn’t in shape and hadn’t fully recovered from knee surgery. Griffin mauled and eventually broke Rua to pull off the huge upset.

Honorable Mention: Kazuyuki Fujita over Mark Kerr, PRIDE GP 2000; Anderson Silva over Hayato Sakurai, Shooto: To the Top 7; Couture over Liddell UFC 43; Couture over Tito Ortiz, UFC 44; Kevin Randleman over Cro Cop, PRIDE Heavyweight GP, 2004; Ricardo Arona over Wanderlei Silva, PRIDE Middleweight GP 2005; Rameau Thierry Sokoudjou over Arona, PRIDE 34;
Anderson Silva over Rich Franklin, UFC 64; Rashad Evans over Chuck Liddell, UFC 88; Frank Mir over Antonio Rodrigo Nogueira, UFC 92.