PHOTOS: Pacquiao's career on the line in Macau

Manny Pacquiao will be fighting for his country and his career on Sunday morning when he takes on American Brandon Rios in the first major international fight card to be held in the gambling capital of Macau.

The bout is taking place in the devastating aftermath of Typhoon Haiyan, which smashed into Pacquiao's native Philippines on November 8, killing more than 4,000 people and leaving another 4 million homeless.

Eight weight World champion Pacquiao, who is also a congressman from SaranganiProvince, said that the tragedy is inspiring him to succeed.

"I am more motivated for this fight, to win this fight because what happened in the Philippines," he said. "My countrymen, I want to make them happy. To bring honour to my country."

For Pacquiao, victory is also essential to maintain an exceptional career that has stuttered of late, following a controversial points defeat to American Timothy Bradley in June 2012 and a shocking sixth-round knockout loss to old foe Juan Manuel Marquez of Mexico in December.

The Marquez defeat was his last ring outing, and the Filipino icon, 54-5-2 (38 KOs), said that the extra time between bouts has left him feeling refreshed and ready for action.

"It's good for me to have a rest like this," he said. "I feel like I'm hungry to fight again in the ring. I feel like when I was starting boxing."

However, Rios' trainer Robert Garcia, while paying respect to Pacquiao's ring achievements in the past, thought the timing might be perfect for his fighter to score an eye-catching victory.

"We know that Pacquiao has been a great champion, considered perhaps one of the best in history," he said.

"But we've seen the last two years, the last two fights, there are some differences, there are some changes, and especially his last fight when he got knocked out.

"We don't know, nobody knows, how that really affected him. We've seen other fighters, and I would say nine out of 10 are never the same."

Former lightweight champion Rios, 31-1-1 (23 KOs), is, like Pacquiao, coming off a loss - via decision to Mike Alvarado in March. But like his trainer, he believed he was facing a legendary opponent at just the right time.

"Pacquiao, in his last fight, wasn't as fast as he was in previous fights," he said.

"I think he has slowed down a lot. You could see that his legs were cramping up as well. I don't know what's going on. Maybe it's his age. It's amazing: when the body says it's time to go, it's time to go."

Both Rios and Garcia feel their best chance is to withstand early Pacquiao pressure and to come on strong in the second half of the fight. Pacquiao, however, allowed himself a wry smile when asked about his opponent's strategy.

"It is easy to say, but to do is not that easy," he said.

Fight week has been marked by tension between the two camps, which erupted on Wednesday into a physical altercation between Pacquiao trainer Freddie Roach and Alex Ariza, Rios' strength and conditioning coach who previously filled the same role on Pacquiao's team.

An argument over training schedules at the gym shared by the two camps during fight week culminated in Ariza kicking Roach in the stomach and security intervening to prevent a wider brawl.

At Wednesday's final pre-fight press conference, Pacquiao called for calm.

"No trash talk before the fight," he pleaded. "It's not a good example for those who follow boxing."

He also refused to be drawn on his foe's assertions that he would send the Filipino into retirement.

"That's his opinion," he said. "He's not greater than God. Only God can tell me to retire."