By Jake Donvan

Cotai Arena, Venetian Resort, Macau, Macau - Manny Pacquiao and Brandon Rios are set to square off at roughly 11:15PM ET (12:15PM local time Sunday afternoon in Macau) in their scheduled 12-round welterweight bout.

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Andy Ruiz Jr. was given a bit of a challenge for as long as Tor Hamer was willing to fight. Luckily for Ruiz, it didn't turn out to be very long at all.

For the second time in less than a year, Hamer opted to quit on his stool, this time tapping out after just three rounds of heavyweight action against Ruiz Jr., who continues to rise in popularity.

The heavyweight bout was fun for as long as it lasted, as both fighters let the leather fly early on. Hamer was the first "B-side" undercard fighter to have his say in any of the preliminary fights, making his presence felt while Ruiz Jr. showed a complete disregard for defense in his best effort to entertain the crowd.

Sturdy chins were shown on both sides of this heavyweight occasion, though Ruiz Jr. picked up the pace considerably in round three. It turned out to be enough for Hamer, who decided to remain on his stool rather than coming out for the fourth round.

The official time of the stoppage was 0:02 of round four.

Ruiz advances to 21-0 (15KO) with the win, though it's impossible to say he has improved. The jiggly heavyweight, who aims to become the first ever from Mexico to win a major title at the weight, came in at a disgusting 257.75 lb, as his weight continues to go in the wrong direction.

Still, there's far more upside to his career than that of his disgraced opponent. Hamer heads to New York with his record falling to 21-3 (14KO), in a performance far too similar to his quit job last December versus Vyacheslav Glazkov live on NBC.

Zou Shiming delivered his most aggressive outing to date in scoring a dominant six-round decisoin over Mexico's Juan Tozcano.

Scores were 60-54 (twice) and 60-52 in favor of Shiming, who was in control from beginning to end.

The knock on Shiming, a three-time Olympic medalist including back-to-back Gold medalis in 2008 and 2012, was his lack of power in the pro ranks. The rate at which he's being moved had most hoping he would be further along in the technical aspect of his game than has been the case thus far.

A deliberate effort was made on the part of Shiming to step up his game on that front, throwing punches with authority round after round while Tozcano never amounted to anything more than a punching bag.

The closest the bout came to being stopped was when time was called for the ringside physician to examine a massive cut under the right eye of Tozcano. It was otherwise a one-way onslaught, a performance not at all dissimilar to that of Verdejo's own win over Duanaaymukdahan in the televised opener.

Shiming improves to 3-0 (0KO), with all three of his pro bouts having taken place in Macau. Tozcano suffers his first pro loss, falling to 4-1 (1KO).

It's been a rough year for boxing in Puerto Rico, but Felix Verdejo continues to keep hope alive for his islanders.

The unbeaten lightweight prospect - a standout member of the 2012 Puerto Rico Olympic boxing team - continues to roll through his first year in the pro ranks. His latest feat came in the form of a six-round shutout over an all too game Petchsamuthr Duanaaymukdahan in the opening bout of the HBO PPV telecast.

Verdejo was precise yet active with his offensive output, slowing picking apart his Thai challenger. The opening round saw the Boricua boxer pump his jab and establish the fight's tempo, picking up the aggression in each passing round.

A sweeping right hand - which came after a straight right just missed its target - put Duanaaymukdahan on his heels early in a third round that never managed to get any better for the underdog. Verdejo offered the entire offensive arsenal in the round, doubling up on his left hook, working his one-twos and never allowing Duanaaymukdahan to plant his feet long enough to land anything of subtance.

The night never got any better for Duanaaymukdahan, who caught a beating round after round. Adding insult to injury, referee Danrex Tapdasan - eager to be a part of the action in a fight that could have easily flown on auto-pilot - issued a meaningless point deduction to the visiting Thai in the sixth round for excessive low blows.

The deduction just made the fight that much wider, as Verdejo won 60-53 on all three cards.

Verdejo cruises to 9-0 (6KO), which comes just seven weeks after appearing on the undercard of countryman Miguel Cotto's ring return this past October. Barely breaking a sweat Saturday evening in Macau, Verdejo is slated to fight again in just three weeks in Puerto Rico.

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Super flyweight Rex Tso (11-0, 7KOs) stopped Susu Sithjadaeng (7-4, 2KOs) in the first round. It was a mismatch, with Tso scoring a knockdown in the early moments and then beating down his opponent until the referee jumped in.

Junior middleweight Kuok Kun Ng (2-0) won a four round unanimous decision over You-Jie Zeng (4-5, 4KOs). All three judges saw it 40-36.

Lightweight prospect Ik Yang (14-0, 9KOs) won a six round majority decision over Hero Tito (7-3, 3KOs) Yang threw and landed the hard punches, and had Tito in big trouble in the final twenty seconds of the fight. The scores were 57-57 for the draw, 60-54 and 59-55.

Super featherweight prospect Harmonito Dela Torre (11-0, 6KOs) scored a third round knockout over Jason Butar Butar (15-12-1, 11KOs).

Jake Donovan is the Managing Editor of Boxingscene.com, as well as a member of Transnational Boxing Ratings Board, Yahoo Boxing Ratings Panel and the Boxing Writers Association of America. Twitter: @JakeNDaBox