Takahiro Ao had been on a strong run since a 2009 loss to Elio Rojas, winning the WBC super featherweight title and defending it three times, but his reign came to an end today in Japan, as veteran Mexican Gamaliel Diaz pulled an upset decision in Tokyo to lift the title in one of the bigger upsets of 2012.

Diaz (37-9-2, 17 KO) figured to be a placeholder opponent, more or less, a tough fighter, sure, and one who had been on his own long winning streak, but still not someone expected to win a major title on the road against a good, young fighter. That's just what he did, though, jabbing his way to a bloody win on scores of 115-111, 114-112, and 114-112.

Ao falls to 23-3-1 (10 KO).

Maybe it shouldn't have been totally unexpected, though, as Diaz was before this best-known as the man who upset both the aforementioned Rojas and 3,572-division world champeen Robert Guerrero when they were unbeaten prospects in 2007 and 2005, respectively. (Between those wins, Guerrero knocked out Diaz in six rounds in a rematch.)

Diaz, 31, scores the biggest win of his career with this one, while Ao, 28, will have to get back in line, either waiting for a rematch, or potentially moving up to lightweight and chasing a world title in a third weight class.