Debuting in the UFC can be a daunting task for even the best fighters in the world. 'Octagon jitters' can often be very real, and even high-level champions have struggled in their first fight on the big stage.
Over the years, though, we have seen a handful of fighters who needed just seconds to make an impact in their UFC debut, putting their opponent away in style.
Some of these fighters went on to achieve genuine success in the promotion, while for some of the others, that flashy debut was their highest point.
Regardless, here are five fighters who needed just seconds to make an impact in their UFC debut.
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#5. Robelis Despaigne - UFC heavyweight contender
The latest fighter to need just seconds to make an impact in their octagon debut was Robelis Despaigne. The Cuban Olympic bronze medallist in taekwondo signed with the promotion last December after winning just four fights on the regional circuit.
Usually, a signing like this would receive plenty of hype, but Despaigne's debut was hidden away on the preliminary card of UFC 299, one of the most stacked events in recent memory.
That meant that few fans were paying any attention to his heavyweight clash with Josh Parisian, which acted as the third bout of the night.
That changed in just 18 seconds. After throwing a missed head kick, Despaigne slipped to the mat, triggering Parisian to charge forward. That turned out to be a major error.
As the brawler dropped his hands, 'The Big Boy' threw a vicious and perfectly-timed right-hand counter that dropped him in an instant and finished him off moments later.
The crowd in attendance went wild for the Cuban, who received a $50k bonus for his efforts. Only time will tell how far he'll go in the division, but it's safe to say that he made a huge impact in his debut.
#4. Todd Duffee - former UFC heavyweight contender
While it's fair to say that he never reached his massive potential, Todd Duffee still holds a place in the UFC's record books. The big heavyweight scored the fastest knockout in the modern history of his division against Tim Hague in his octagon debut back in 2009.
With a cartoonishly muscular physique and intimidating aura, Duffee brought a big reputation with him to the promotion due to the fact that he'd stopped PRIDE veteran Assuerio Silva on the regional circuit.
Few could've expected his debut to be so wild, though. After refusing to touch gloves with 'The Thrashing Machine', Duffee strode right into the center of the octagon and decked Hague with a stiff jab.
The Canadian tried to recover, but Duffee quickly pounced with some brutal follow-up shots and knocked him silly, all in just seven seconds.
The fight seemed to be the beginning of the career of a possible heavyweight title contender, but things didn't quite go that way. Duffee lost his second octagon bout, and injuries and personal problems largely wrecked his career.
He did win a further two bouts in the UFC but washed out of the promotion after more issues in 2019 and never quite reached the high watermark of his debut again.
#3. Ryan Jimmo - former UFC light-heavyweight contender
When Ryan Jimmo was signed by the UFC in early 2012, many hardcore MMA fans were largely nonplussed.
'The Big Deal' had put together a fantastic record of 16-1 largely in his native Canada, but he'd also earned a reputation as a dull point-fighter. Indeed, most of his wins had gone the distance.
Few eyeballs were really focused when he made his octagon debut against Anthony Perosh, then, but the light-heavyweight didn't need long to change that.
Jimmo stalked forward, dropped 'The Hippo' with an overhand right, and then finished him off with one more shot that turned out his lights.
From there, as the Aussie lay in a heap, 'The Big Deal' celebrated by busting out the infamous 'robot' dance. Realistically, a seven-second debut like this should've turned Jimmo into an instant star.
Unfortunately, it didn't quite work that way. Jimmo fell to James Te Huna in his next fight, ruining his hype, and never did recreate that explosive debut even in his two further UFC wins. 'The Big Deal' departed the promotion in 2015, and a year later, died in a tragic car accident.
#2. Anderson Silva - former UFC middleweight champion
While his octagon debut lasted a little longer than the ones previously mentioned on this list, it still didn't take Anderson Silva long to make his impact. His first fight saw him dispatch of Chris Leben in just 49 seconds.
The win was monumental for a number of different reasons. Silva had always carried the reputation of a fighter who was hugely talented, but was also mercurial and somewhat inconsistent. Therefore, nobody really knew exactly what to expect when he joined the UFC in 2006.
To add to this, Leben was notoriously iron-chinned, meaning that few fans expected 'The Spider' to be able to put him away, even if he produced his best form.
Remarkably, though, Silva blew expectations right out of the water in a stunning display. He literally landed every strike he threw at 'The Crippler', initially stunning him with a head kick and a rapid-fire combination before finishing him off with knees to the head.
It was the first time anyone had ever finished Leben, and somehow, Silva had made it look easy. In terms of making an impact in his first trip to the octagon, it didn't get any better.
The debut could easily have ended up being the Brazilian's high point. Of course, though, he claimed the UFC middleweight title in his next fight and then produced one of the most dominant reigns of all time.
#1. Frank Shamrock - former UFC middleweight champion
Naturally, the biggest possible impact that any fighter could make in their octagon debut would be to win a UFC title. It's a feat that has always been exceedingly rare, even in the promotion's early days.
However, legendary former 205-pound champ Frank Shamrock not only did this, but he also needed just 16 seconds to do so. It was a ridiculous achievement that still stands the test of time nearly three decades on.
Shamrock was no rookie when he finally made his way to the octagon. The adopted brother of MMA pioneer Ken Shamrock, Frank, had put together an extensive record fighting in Japan.
It was this impressive reputation that led the UFC to book him against Olympic gold medallist Kevin Jackson in a fight to decide the inaugural middleweight (now light-heavyweight) champion at the end of 1997.
A phenomenal wrestler, Jackson unsurprisingly took Shamrock down in the fight's opening seconds, but before he could make his next move, his one-dimensional skillset was exposed. Shamrock applied a simple armbar from the guard and forced him to tap out instantly.
It was an insane finish, and the new champion literally didn't even eat a punch in the process of winning. Shamrock would go on to defend his title successfully on four occasions, and while he's now persona non grata with the promotion, to those who remember him, he'll always be a legend.