Guillermo Rigondeaux is trying to build an audience, but he's just 11 fights into his professional career, and his personality is on the south side of engaging.

The two-time Olympic champion from Cuba is something to watch in the ring, however, as he proved Saturday in defending his World Boxing Assn. super-bantamweight title with two knockdowns in a unanimous decision over Mexico's Roberto Marroquin.

 

Guillermo Rigondeaux, right, throws a punch against Roberto Marroquin during a WBA super bantamweight title match.(Julie Jacobson / Associated Press / September 15, 2012)

Judges Glenn Feldman and Robert Hoyle scored the bout 118-108, and Ricardo Ocasio had it 118-109.

"He's very sneaky and complicated, difficult to fight," Marroquin (22-2) said. "That's why he's the best 122-pounder out there."

The action preceded Saturday's middleweight title fight between champion Julio Cesar Chavez Jr. (46-0-1, 32 knockouts) and former champion Sergio Martinez (49-2-2, 28 KOs) of Argentina, which was not complete at press time. Check latimes.com/sports for full coverage.

Rigondeaux had his way with Marroquin early, remaining patient with his head tucked behind his right shoulder, smacking Marroquin with hard lefts the instant the challenger attempted to come forward.

In the third round, Marroquin ducked a jab from the left-handed Rigondeaux and belted him with a left that nearly dropped the champion.

Yet, Rigondeaux quickly reverted to the systematic method that made him a two-time Olympic champion, and he knocked down Marroquin on one knee in the fifth by slashing inside to deliver a hard left flush to the face.

Rigondeaux (11-0) again knocked Marroquin down in the 12th after opening a cut on the bridge of the challenger's nose.

The champion fired a rapid left to the side of Marroquin's head, then followed with a straight right to the nose as Marroquin fell.

Fight promoter Bob Arum of Top Rank foresees a bright future for Rigondeaux, though the Cuban nearly withdrew from Saturday's date because of a legal dispute last month with Arum.

The matter was settled to the point Rigondeaux returned to the ring, and the sides are negotiating a possible 18-month extension that would give Rigondeaux three to five fights during the period with guaranteed minimum payments.

"I haven't slept in two days," Rigondeaux said. "So many things happening. I'm fighting, not fighting, fighting again. Marroquin was in tough condition. That's why it went 12 rounds."

If agreed upon, Arum's deal would leave Rigondeaux in line for a possible date with International Boxing Federation and World Boxing Organization champion Nonito Donaire (29-1, 18 KOs), should Donaire defeat Japan's Toshiaki Nishioka on Oct. 13 at the Home Depot Center.

Asked whether he too believes he's the best 122-pounder in the world, Rigondeaux said, "I'm working on it."

England middleweight Matthew Macklin (29-4), defeated by Martinez in March, returned to dominate Canada's Joachim Alcine, winning by first-round technical knockout after knocking down Alcine twice earlier in the round.

Referee Jay Nady stopped the fight at the 2:36 mark.

In a thrilling battle for the vacant World Boxing Organization super-featherweight title, Ramon "Rocky" Martinez of Puerto Rico edged Mexico's Miguel Beltran by split-decision.

Judges Duane Ford and Clark Sanmartino scored it 114-113 for Martinez after Beltran had an 11th-round point deducted for punching behind the head. Judge Lisa Giampa scored it 116-111 for Beltran.

Before the pay-per-view fights began, Notre Dame product Mike Lee (11-0) continued his cushy ride in the fight game, defeating Paul Harness (4-4-1) by unanimous decision (40-36 on all three scorecards).

Lee, who's been featured in Subway commercials, has been fed a string of soft touches by Top Rank matchmakers who've done a superb job ensuring Lee remains unbeaten.

lance.pugmire@latimes.com

twitter.com/latimespugmire