Tim Bradley (L) and Manny Pacquiao exchange punches during their April 12, 2014, rematch at the MGM Grand. Photo by Jeff Gross/Getty Images.

LAS VEGAS — Top Rank CEO Bob Arum ripped Floyd Mayweather Jr. and the MGM Grand for what he called the "thug mentality" of advertising Mayweather's upcoming Showtime Pay Per View fight with Marcos Maidana during the days leading up to Saturday night's unanimous decision by Manny Pacquiao over Tim Bradley on HBO Pay Per View.

Arum made his most recent comments during the press conference after Pacquiao had dethroned Bradley as WBO beltholder, regaining the belt he lost by disputed split-decision to Bradley in June 2012.

With Mayweather being contractually bound to HBO's network rival Showtime, Arum was asked if a long-awaited Mayweather-Pacquiao bout could be arranged in similar fashion to Lennox Lewis vs. Mike Tyson in June 2002, when the fighters were affiliated with HBO and Showtime, respectively.

"If people operate in good faith and want to get something done, everything is possible. It's no reason to take threats and preconditions and say that is immutable," said Arum from his position behind the podium. "Everything can be negotiated, and everything should be negotiated. I don't think there's a downside for anybody about sitting down and making it happen. I really don't."

Then, Arum segued into his issues with the overlap of the Mayweather-Maidana promotion into that for Pacquiao-Bradley II.

"Any excuses for it not happening is posturing and exhibits, in my mind, the same thug mentality that we saw in getting the MGM to hang posters for a fight that is three weeks away," said Arum. "I've never seen that in my time. That's never been done before. That's thuggery. I wouldn't in a million years think of asking any venue to do something like that."

Martin Rogers of Yahoo!Sports called Arum's comments "borderline racist," and Showtime Sports boss Stephen Espinoza said they were "indefensible" during an interview with RingTV.com.

"I think that it's beyond offensive for him to use terminology that has those kinds of racial overtones. It's at least the second time this week that he's gone way over the line," said Espinoza, during a phone interview with RingTV.com.

"I'm starting to worry about his mental state given his behavior over the last few days. It's interesting to say the least to see Bob's reaction when things don't go his way. When he's been out-maneuvered and other people have a contractual advantage on him, for him to throw tantrums and throw around words like 'thuggery' and 'thug mentality' is indefensible."

Informed of Espinoza's response, Arum retorted.

"Stephen Espinoza is a horse's ass of all horse's asses," said Arum. "With what he has done to hurt boxing, he is a real blight on the sport of boxing."

Neither Golden Boy CEO Richard Schaefer, with whom HBO has severed ties, nor Leonard Ellerbe, CEO of Mayweather Promotions, could be reached for an immediate comment.

But Ellerbe defended the MGM's support of Mayweather-Maidana during a Saturday afternoon press gathering attended by Maidana at Wolfgang Puck's restaurant.

"Floyd Mayweather is the biggest star in boxing. Period. Hands down. If any casino or company that we're affiliated with doesn't stand behind him, then it is what it is," said Ellerbe. "I mean, people come to see Floyd Mayweather fight in big events. That's why we do the kinds of numbers that we do. There's no comparison."

ESPINOZA: THERE IS A DIFFERENCE BETWEEN MAYWEATHER-PACQUIAO AND LEWIS-TYSON

"There's one huge difference. Lennox Lewis had an exclusive contract with HBO," said Espinoza. "There's no reason that HBO should be part of a Floyd versus Manny fight when HBO didn't even bother to sign Manny to an exclusive contract."

Pacquiao's advisor, Michael Koncz, confirmed that Pacquiao is not contractually bound to HBO.

"We're free agents," said Koncz. "We do not have a contract with any network. We're free agents."

PACQUIAO WON, BUT NOT WITHOUT A STITCH

Pacquiao (56-5-2, 38 knockouts) required 32 stitches to repair a more than 2.5 centimeter wide laceration suffered over his left eye from an accidental clash of heads with Bradley (31-1, 12 KOs) during the final round.

The surgery required nearly an hour, after which Pacquiao addressed media members during a post-fight press conference.

BRADLEY OFFERS 'NO EXCUSES'

Bradley said that he went for the knockout believing that was his only chance to win. As a result, he chose to fight toe-to-toe, abandoning what he perhaps does better, which is box and move, in order to pursue the unlikely knockout.

Both Pacquiao and his trainer, Freddie Roach, acknowledged that Bradley had hurt Pacquiao in the fourth round.

Bradley, for his part, offered no excuses, even as he limped into the post-fight press conference after having apparently suffered a strained right calf muscle as early as the first round.

"That's the only way that I was going to win the fight … I knew that the rounds would be close. Pacquiao's very experienced. He knows how to land punches, and if I don't knock this guy out, I knew that there would be too many close rounds," said Bradley.

"So I was just shooting for it and going for the knockout, just like I told everybody that I would. I tried to go for it, man. He said that I hurt him in the fourth round, with a big shot over the top. I tried to finish him, but he's really experienced in the ring. He's in tremendous shape, and he recovered just like that. He got his distance and recovered and was firing right back."

Pacquiao had an overall advantage in punches landed (198-to-141), and power shots landed (148-to-109), according to CompuBox.

"I have no excuses tonight. Pacquiao was the better man tonight. The dude still has it," said Bradley, who fought with limited mobility during their first fight after having injured his left and then right foot in the second and fourth rounds, respectively.

"The reason I love Pacquiao is that he doesn't duck his opponents. He's always willing to face the best. He faced one of the best tonight, and he came out on top. So Manny Pacquiao is a true champion. He's an unbelievable champion. I have nothing but respect for him and his team. I accept defeat like a man."

As for what he will do next?

"I lost tonight, but the war is not over. Time to go back to the gym. Time to go back to the gym and get better. This just means that I need more work. I will become champion again."

ARUM: BRADLEY'S STOCK 'DID NOT GO DOWN, IT WENT UP'

In his past four fights, Bradley has beaten Pacquiao, risen from a 12th-round knockdown to unanimously decision Ruslan Provodnikov, split-decisioned Juan Manuel Marquez last October, and lost to Pacquiao.

Choosing to wage war against Pacquiao improved Bradley's attraction, Arum said.

"The Bradley that fought Pacquiao the first time is not the Bradley who fought him tonight. This was a Bradley who was very, very confident," said Arum.

"The value of Timothy Bradley tonight, even though he lost, did not go down, it went up. Everybody who follows boxing is going to want to see Tim Bradley's next fight."

MAYWEATHER-MARTINEZ?

"No. Not at all. Right now, Martinez is a middleweight," said Ellerbe, who doubted even if the bout could take place at a 155-pound catchweight. "I don't know what his situation is as far as his network, and if he has a situation with them. I don't know. I know that we're in control of our destiny."