Technical knockout, second round. TKO, third round. KO, TKO and TKO, all in the first.

That's how José Aldo exploded onto the scene of American mixed martial arts nearly six years ago. The last of those five fights during his early days in the WEC was as brisk as it was brutal. His eight-second flying-knee destruction of Cub Swanson earned him a shot at the featherweight title.

Aldo seized the opportunity, knocking out champion Mike Brown in the second round, just as he seized every opportunity, exploited every opening, devastated every opponent. The Brazilian was a buzzsaw, an unrelenting assault of flailing fists, flying knees and heart-thumping finishes.

But ever since Aldo captured the belt in the late fall of 2009, opponents haven't been falling with quite the deadened thud of the old days. When the 25-year-old steps into the octagon Saturday night in Rio de Janeiro for the main event of UFC 142, he will be making his fifth title defense, his third since the featherweight division moved to the UFC. So Aldo (20-1) has been winning, even doing so in dominant fashion. However, three of his four challengers have taken him the full five rounds.

That's Chad Mendes' game. The 26-year-old Californian who will challenge for the title this weekend is a decision machine. The 2008 NCAA Division I wrestling championships runner-up is 11-0 in MMA, with the last five of those wins coming in the two years since he joined the WEC/UFC. All but one of his victories in the game's top promotion have been by decision -- unanimous decision, in fact, with Mendes barely losing a round.

The same has been true of Aldo's decision wins. So something has to give. The judges, once-idle bystanders at Aldo fights, will be wise to pay close attention this time.

13: Consecutive victories, with his last loss coming way back in 2005.

94: Percent of takedown attempts successfully defended in his 10 UFC/WEC bouts, according to FightMetric statistics. In his last fight, Aldo fended off 18 of Kenny Florian's 19 takedown tries.

4: Reach advantage, in inches.

74: Percent of strikes avoided during his six UFC/WEC fights, according to FightMetric stats.

40: Months since he became a professional mixed martial artist (Aug. 26, 2008).

0: Five-round bouts, this being his first title challenge.

What we should expect: It's going to be a turf battle. Aldo and Mendes each will be fighting to keep the bout in his comfort zone. Mendes will try to explode through the champion for a takedown, putting himself in position to control the fight, like he has all previous ones. Aldo, a versatile striker who can hurt an opponent from any angle, will do all he can to keep the fight standing until he can take it to the mat on his terms -- that is, by knocking down the challenger, then jumping on him and raining down fists.

Why we should care: The featherweight belt is on the line, and so is the future of the weight class and, to an extent, the sport itself. Aldo is 25, Mendes 26, and while neither has captivated the imagination of American fans quite like 24-year-old light heavyweight champion Jon Jones (who has?), this is an opportunity to make a statement. Aldo, fighting in Brazil for the first time in nearly five years, could earn a little Anderson Silva love from the home fans with an exhilarating victory.

"He's the one with the pressure. He's the champ. He's the headliner in his own town, while I am the up-and-comer, the underdog. There's no pressure on me." --Chad Mendes, speaking of José Aldo during a conference call with MMA media

"This is where I started, just with dreams and hopes, and now I am back as a champion." --Aldo, through a translator, during the same conference call

"Other fighters have stood there and let him take them apart. I think I will get in there and get my hands on him. No one else he's fought has my level of wrestling, to where I will get him down and keep him down." --Mendes

"I found a few things in his game I can exploit. Nobody is perfect. Everyone has holes in their games, me included." --Aldo

"The Aldo camp saying I am not ready for a title shot? They don't know how good I am." --Mendes

It'll be a Rumble: Anthony Johnson has earned the nickname "Rumble" by scoring 10 of his career wins by KO. Well, how do you say rumble in Portuguese? Vitor Belfort has done exactly twice as much rumbling, with 14 KO's among his 20 victories, and his last four bouts all have ended in the first round. (In one of them, he was on the receiving end of the finishing strike, a highlight-reel jumping front kick to the face courtesy of Anderson Silva.) This fight promises to be an all-out throwdown, which should only drum up interest in the first season of The Ultimate Fighter: Brazil, on which Belfort will serve as a coach along with fists-flying countryman Wanderlei Silva.

Predicting a Brazilian win: As was the case when the UFC was in Rio for UFC 134 just five months ago, this card is filled with Brazilian fighters. Every one of the evening's 10 bouts has at least one man competing in his home country, and two fights pit Brazilian vs. Brazilian. Aside from Belfort, the most notable name is former heavyweight title challenger Gabriel Gonzaga, who in 2007 knocked out Mirko CroCop to earn a shot at Randy Couture (the reigning champ won by third-round TKO). Gonzaga, out of the UFC for over a year, returns against Edinaldo Oliveira, an undefeated (13-0-1, 1 NC) fellow Brazilian making his UFC debut. Other up-and-coming Brazilians on the card: Erick Silva (13-1, 1 NC) puts a 10-fight unbeaten streak on the line against Carlos Prater, and Edson Barboza (9-0) faces Terry Etim.

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