By Jake Donovan

Carlos Cuadras recorded the fifth successful defense of his super flyweight title, outpointing Koki Eto over 12 rounds Saturday evening in Sendai, Japan. 

The bout was one of two on the evening pitting defending titlists from Mexico versus challengers from Japan. The co-feature bout saw one of the year's biggest upsets as Yu Kimura claimed a split decision win over Pedro Guevara to win the junior flyweight title.

Taking note, Cuadras made sure to not suffer the same fate. Both bouts eerily jumped out to a similar start, however, with the challengers appearing to be overmatched. 

Cuadras was quick out the gate, showing why he is regarded as high among the best super flyweights in the world. His hand speed was too much for Eto, who was outboxed in the opening round and badly hurt in round two before quickly rallying to avoid an early knockout. 

One thing about Cuadras' reign has been the lack of true knockout power despite the glossy KO to win percentage. Eto was able to absorb the defending champion's best shots and continue to come forward, although he wasn't winning any rounds. Cuadras was up 40-36 on all three cards after four rounds as revealed by World Boxing Council (WBC) open scoring and - like Guevara an hour before him - proceeded to enjoy a huge round five.

As was the case in the previous bout, the challenger turned the tide in round six. Eto enjoyed his best three-minute stretch of the fight to that point, walking through Cuadras' punches to score his own shots. He once again took everything the defending champ had to offer in round seven, only he was no longer throwing back as much in return - not the best way to win a title, even in your own home land. 

Whereas Guevara ran out of steam in the second half of his loss to Kimura, Cuadras knew when to bang and when to box in his title defense. The visiting champion from Mexico was far ahead after eight rounds 79-73 (twice) and 78-74 - to where Eto was going to need a knockout to win. 

That moment never came, although the challenger enjoyed a nice rally over the final four rounds. Cuadras took note, sticking and moving down the stretch rather than pursuing a knockout opportunity that clearly wasn't present. It wasn't the type of performance that will necessarily make the highlight reel, but one that ensured the king remaining the king. 

Scores of 117-111 (twice) and 116-112 all came in for Cuadras, who advances to 34-0-1 (26KOs). One of the more active titists in the sport, the bout marked the fifth defense of the belt he claimed in a technical decision win over Srisaket Sor Rungvisai last May.

As Sor Rungvisai has manuevered back into the mandatory challenger slot, a rematch with the former champion from Thailand is likely next for Cuadras, who is now 6-0 in Japan. His last fight in the Far East came right before he won the title, claiming a stay-busy win on New Year's Eve in 2013. 

Eto falls to 17-4-1 (13KOs), snapping a three-fight win streak in the process. The 27-year old from Tokyo - about four hours south of Sendai - had previously enjoyed a brief reign as an interim flyweight titlist, but came up short in his first crack at a real title. 

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