Mirko Cro Cop, UFC Fight Night 64's 'Fighter to Watch' today on Fight Pass

Their names may not resonate with a more green mixed martial arts (MMA) fan, but for the long-time viewers of the sport; the names Mirko "Cro Cop" Filipovic and Gabriel Gonzaga are synonymous with one of the biggest and most odd upsets in Ultimate Fighting Championship (UFC) history.

Fight fans prepare for a night of nostalgia when Filipovic and Gonzaga partake in another Octagon romp at UFC Fight Night 64 in Krakow, Poland today (Apr. 11, 2015). The pair previously fought at UFC 70 in April 2007, with the Brazilian getting the better of the Croatian fighter via head-kick.

Rounding out the main card, which will be broadcasted live on UFC Fight Pass, are bouts containing the power-punching Brit Jimi Manuwa and top ranked women's strawweight Joanne Calderwood.

A majority of the fighters on this rare afternoon UFC spectacle are still in their prime and have years of Octagon time ahead of them, but not 40-year-old Filipovic. His return after a three-year hiatus seems more like one last hoorah, if anything.

The fighter who was once known for his deadly left head-kick has managed to scrape together a 3-1 record in his last four fights (all of which were in Japan). But prior to those wins, Filipovic found himself on the wrong end of some vicious beatdowns, which ultimately led to his retirement from MMA.

He may not be fighting for a title at this point in time, but his legacy in the sport has already been written. In his heyday, his head-kicks were revered and menacing; Cro Cop could snap one off on a whim.

The Croatian's highlight-filled career began 14 years ago in the storied PRIDE promotion. Filipovic took no prisoners and compiled a laundry list of notable names for victims.

He had difficulty making his presence felt early in Japan, fighting to two draws against Nobuhiko Takada and Wanderlei Silva. His fight with "The Axe Murderer" set the tone for what was to come as it showcased his resilience to withstand a potent offensive attack.

Future Japanese legend Kazushi Sakuraba was next on Filipovic's docket. The two engaged in a mildly-entertaining tilt, with no fighter dishing out any significant amount of damage, but the fight was called after two rounds because of an eye injury to Sakuraba.

Filipovic was gradually getting a taste of the various styles in MMA; just as fighters were getting acquainted with his devastating knockout power. Sakuraba was able to ground the Croatian and he even dropped him with a straight left-hand.

After (3-0-2) start to his career, Filipovic would soon find his groove. He enjoyed a dominant stretch in 2003, notching victories over Heath Herring, Igor Vovchanchyn and Dos Caras Jr. Two of those wins came via his illustrious head-kick.

It was right leg, hospital; left leg, cemetery. Fighters didn't know which way, at what speed or ferocity that his missiles of legs were coming from.

The K-1 kickboxing extraordinaire then met Brazilian jiu-jitsu black belt Antonio Rodrigo Nogueira in what was one of the best fights of 2003. With a title on the line, Nogueira and Filipovic went to war for a little over five minutes, before the striker succumbed to the grappling prowess of his opponent.

It was Filipovic's first legitimate loss and a critical point in his upstart fight career. Would he flame out, or continue on to stumble to a simply mediocre tenure in Pride?

The latter would not be the case. From that point onward, Filipovic established his name and cemented his place in the record books.

For 15 years, he picked apart the world's best in one of the greatest promotions ever assembled. And he did it without much talking, music or pyrotechnics. Cro Cop was just Cro Cop.

Much like his terrifying head-kicks, the beauty wasn't in his power, but instead his grace. His fight trunks became a staple of his character and country, while his staredowns signaled the beginning of the end for most men.

Alexander Emelianenko, Josh Barnett (three times), Kevin Randleman, Mark Coleman and Silva all fell to Filipovic over the next two years. Among those bouts were some of his most historic knockouts to date, including this doozy against the Brazilian Silva.

But it was his part in a pivotal loss that was perhaps his most memorable contribution to the fight game. In August 2005, Filipovic battled pound-for-pound great Fedor Emelianenko.

The 2000's Fight of the Decade was contested on the feet and the mat. Filipovic flustered the Russian brute on multiple occasions but was stymied in the end by the latters' impressive background in Sambo.

Though he fell to 0-2 in title fights with the loss to "The Last Emperor", Filipovic rode an uncontrollable hype-train into the UFC in 2006. Eddie Sanchez was toast in his debut, but then came the unexpected.

Gonzaga, a fighter known for his jiu-jitsu skills, took out the elite striker with a startling right head-kick -- the one that Filipovic so famously employed while in Pride. It was like the world was flipped upside down, could it be?

Things would go from bad to worse for him. After a lopsided decision-loss to French striker Cheick Kongo, Filipovic was released from the UFC.

Two quick wins over lackluster competition in Japan would be all the UFC needed to bring him back stateside. His last stint in the promotion lasted from 2009-2011 and brought forth mixed results.

Wins over Mostapha Al Turk, Anthony Perosh and Pat Barry were compounded by underwhelming efforts against foes like Roy Nelson and Frank Mir. What stands out from that list of names is a clear discrepancy in talent level.

Filipovic succeeded against those he was expected to beat, but when he took a step up in competition, he faltered. It is then obligatory to ask: how was he able to thrive against elite fighters in Japan but not in the UFC?

Two answers come to mind: damage taken and age. Filipovic was in his mid-30s during his most recent stint. The majority of his notable Pride wins came before he hit the age of 30.

Damage wise, Filipovic ate some blows but spent far less time in the squared circle than most. In 18 PRIDE victories, he accrued close to 109 minutes of ring time.

At 40, Cro Cop doesn't have much left to give to MMA (sorry to be frank), nor does he have much to prove. The man still has a big following and will be fighting for the 45th time.

So even though his rematch with Gonzaga may only excite seasoned fans of the sport, it's still worth your eyes and ears. Fight on, Cro Cop!

Remember, too, that MMAmania.com will provide LIVE round-by-round, blow-by-blow coverage of the entire UFC Fight Night 64 fight card, starting with the Fight Pass "Prelims" matches online, which are scheduled to begin at 11:45 a.m. ET, right on through the Fight Pass-only main card, which is slated to begin at 3 p.m. ET.