TJ Dillashaw's career-defining victory over Renan Barao reminds us why we love this sport

Long before T.J. Dillashaw landed the big overhand right that dropped Renan Barao in the opening round of his bantamweight title winning performance at UFC 173, the shared opinion on his chances of survival went from "don't see anyway he wins" to "is this really happening?" very quickly.

Admittedly, I had the +725 underdog fitted for a casket when it was announced that the Sacramento-based fighter would be stepping in for the injured Raphael Assuncao to face Barao, the killer from Nova Uniao who was crushing everyone he fought.

After all, this was T.J. Dillashaw, the same bantamweight who got knocked out by John Dodson in the The Ultimate Fighter (TUF) 14 Finale. The same bantamweight -- who although looking impressive in his last few fights -- had only a win over Mike Easton to boast as his biggest victory in the UFC.

I, along with many others thought, "It's way too soon for him to be taking on the likes of Barao."

More so was the fact that the Brazilian had just defeated Faber for the second time -- knocking the Team Alpha Male leader from pillar to post at UFC 169 -- and finished off Eddie Wineland with a spinning back kick, and Michael McDonald with a side-triangle before that.

So how in the world was Dillashaw going to stand a chance?

Yet there he was right from the start, executing a masterful gameplan thought out by Duane Ludwig, the striking coach who brought the level of striking to a whole new level for the Team Alpha Male squad and was brought to tears after seeing his fighter hoist the belt. Dillashaw marched forward right from the start, landing leg kicks and moving in and out, switching from southpaw to orthodox and firing from all different angles. Barao could not figure him out and thus could not mount any significant offense.

The next four rounds were all a carbon copy of the first. Dillashaw was putting on a clinic in the biggest fight of his life against an opponent, who according to oddsmakers and almost every expert, he didn't belong in the Octagon with.

Watch the video highlights here.

It was simply beautiful to watch, A) because of how great Dillashaw performed and how technical his striking looked and B) because it was a pleasant surprise that reminded us why we watch and cover this sport in the first place: for the unknown, the unexpected, the "how in the world did we not see this coming" moments that don't happen every time out or every time we tune in.

We were getting one of the most memorable moments with every big strike Dillashaw was landing and every move he was making.

The TUF 14 runner up didn't land a big punch and finish on the ground for an upset like Matt Serra, whose upset over Georges St-Pierre at UFC 69 is still the biggest underdog victory to date. He almost did that in the opening round after connecting with the big right hand and trying for a rear naked choke. What makes his upset special and very unique, is the fact that he dominated the former bantamweight champion for four-plus rounds until closing the show midway through the fifth round with the big head kick and the barrage of punches that followed.

Had he knocked out Barao in round one, or snatched that rear naked choke for the victory, sure it still would've been a massive upset, but we would've been robbed of one of the greatest performances by an underdog in UFC history and it could've been analyzed as Barao "got caught," and "it happens."

Instead, we all got to witness what Joe Rogan was calling "one of the greatest, if not the greatest performance by an underdog in a UFC fight that he's ever seen" and he's right. Dillashaw not only defied major odds to win in a career-defining performance, he made Barao look foolish.

The Barao that UFC and Dana White were marketing as the No.1-pound-for-pound fighter in all of MMA, Dillashaw outstruck him by a margin of 169-68 (according to Fightmetric). A knockout in round one and we would never have seen or believed he could dominate Barao, who up until last weekend was always masterful at making adjustments in fights.

Had a casual fan who didn't know either fighter tuned in last Saturday night, they would've thought it was Dillashaw who was the champ and the huge favorite, not Barao and that in itself is what separates this fight and puts it into its own exclusive category.

We witnessed the physical aspect in regards to the new champion's performance, but how about the mental one?

In the biggest fight of his young career -- he's only 7-1 in the UFC -- his confidence was through the roof. If you are old enough to remember the movie Vision Quest, then you remember Mathew Modine's character, Louden Swain, who wanted to face Shute, the state champion wrestler who no one could beat. Swain was a huge underdog, but was convinced he could take him, much like Dillashaw was that he could defeat Barao. Except, of course, had Swain performed like Dillashaw, he would've won by technical fall.

The first-ever Team Alpha Male UFC titleholder told reporters at the post-fight press conference (watch it) he ignored all the hype on Barao and possessed the right frame of mind to match up against him.

"You got to ignore it," Dillashaw said about the pre-fight build up of Barao. "Obviously you hear it. You hear how awesome the guy is. It's just the mental mindset for competition. You cant go into a competition scared. If you are you are not going to be to your fullest. I went in there with a 100-percent belief, even though I knew how great the champion was, I just had to believe in myself."

The UFC bantamweight title now resides in Sacramento at Team Alpha Male, but it's not Urijah Faber's belt, or Chad Mendes' either. It belongs to Dillashaw, who joins Rashad Evans, Forrest Griffin and Matt Serra as the four TUF contestants to go on to win a UFC title.

"It's crazy," Dillashaw said after being asked about that fact.

It definitely is.

An amazing performance. One we never saw coming and one we desperately needed among all of the sports oversaturation and limitless fight cards. It's been quite some time since we saw a moment like this on the biggest stage of MMA, if ever, and one we may not see for quite some time again.