The Mayweather vs Ortiz HBO pay-per-view event starts this evening at 9 p.m. EDT, and we'll have live coverage of all four fights on the main show. The three televised undercard bouts will be covered, round-by-round in this thread, with a separate post dedicated to the main event.

Here's what you'll see on tonight's undercard:

Junior Middleweights, 12 Rounds (WBC Title)
Saul "Canelo" Alvarez (37-0-1, 27 KO) vs Alfonso Gomez (23-4-2, 12 KO)

21-year-old phenom Alvarez is actually main eventing his own show tonight in Los Angeles at the Staples Center, facing 30-year-old battler Gomez for Alvarez's WBC junior middleweight title. It's a fight that should have good action, as Gomez isn't a cutie in there by any means, but Alvarez is the clear favorite, with large betting odds in his favor, and few giving Alfonso a serious chance to pull the upset.

Junior Welterweights, 12 Rounds (Vacant WBC Title)
Erik Morales (51-7, 35 KO) vs Pablo Cesar Cano (22-0-1, 17 KO)

Young Cano, 21, is a late-notice substitute for Lucas Matthysse, the Argentine contender who would have been favored by most to win this fight. But 35-year-old Morales looked his age and his ring age at yesterday's weigh-in, so despite the fact that on-paper, he's the obvious favorite in a big way, this could be interesting if Cano can press early.

Junior Welterweights, 10 Rounds
Jessie Vargas (16-0, 9 KO) vs Josesito Lopez (29-3, 17 KO)

22-year-old Vargas is Mayweather-promoted and endorsed, but this is a step up for him against Goossen Tutor's Lopez, a 27-year-old coming off of a career-best win eight months ago. This could be a show-stealing action fight.