By Jake Donovan

Nonito Donaire is once again in possession of a super bantamweight title, but had to work harder than ever before in outlasting a relentless Cesar Juarez in their savage 12-round war Friday evening at Coliseo Roberto Clemente in San Juan, Puerto Rico. 

Scores were 116-110 (twice) and 117-109 in favor of Donaire, who scored a pair of 4th round knockdowns, but had to overcome cuts, injuries and strong second half surge from Juarez to prevail.

For five-plus rounds, Donaire did everything he expected to do in a bout he was heavily favored to win. Juarez looked every bit the massive underdog he was perceived to be, as he was beaten to the punch and taking punishment to the point where it seemed like a matter of time before the fight would be stopped. 

An early night seemed well in the works after Donaire floored Juarez twice in round four. A right hand shot produced the first knockdown of the night, with Juarez being sent right back to the canvas moments later courtesy of a left hook. 

Juarez managed to survive the round. What followed was eight rounds of two-way brutality that turned a perceived mismatch and rout into a bona fide Fight of the Year candidate.

Donaire slowed down just enough in round five to allow his wounded prey to shake loose the cobwebs. Juarez slowly began to make his presence felt, picking up the pace in round six and never looking back.

What once seemed like a knockout win soon became a race against the clock for Donaire. The 33-year old Fil-Am star had a left eye that was beginning to swell shut and a cut over his right eye. Another scare came late in the round, when he arose from a slip hobbling on his ankle. 

More concerning was the fact that his energy level dramatically decreased in the second half of the fight. Despite just 20 fights to his name heading in, Juarez was wise enough to pick up on his opponent's declining stamina, going to the body as he began to wear down Donaire. 

You can take your pick from a number of rounds in the second half in which to honor come year-end awards seasons. Rounds eight, nine and ten were particularly brutal, with Donaire laying along the ropes, doing his best to pick off the incoming but catching plenty of right hands and left hooks for his troubles. 

All that was keeping the former four-division in the champ was his fighting heart and occasional counter left hook. Juarez threw caution to the wind in order to land his shots, which meant leaving himself open on the occasions Donaire was able to return fire. 

While momentum dramatically shifted, the underdog brawler from Mexico still needed a knockout to win heading into the 12th and final round. It never threatened to happen, no matter how hard he tried. That's because Donaire dug deep to throw more than the occasional counter shot, landing hard left hooks and right hands to remind Juarez why he was favored to win. 

It was enough to finish the fight on his feet and - with the win - begin a second tour as a super bantamweight champ. Donaire picks up his third straight win as he improves to 36-3 (23KOs). 

Juarez falls to 17-4 (13KOs), ending a Cinderella run that included upset wins over Cesar Seda and Julio Sanchez Jr. earlier this year.

The bout aired live on truTV in the 2015 season finale of Top Rank's

Metro PCS Friday Night Knockout

series. 

Jake Donovan is the managing editor of BoxingScene.com. Twitter: @JakeNDaBox