Floyd Mayweather beats Manny Pacquiao: Here's how the action unfolded

Las Vegas: Floyd Mayweather defeated Manny Pacquiao by unanimous decision on Saturday in their long-awaited welterweight world title showdown.

In a bout branded boxing's latest "Fight of the Century" Mayweather took his unblemished record to 48-0 adding the Filipino great's World Boxing Organization title to his World Boxing Association and World Boxing Council crowns. Pacquiao fell to 57-6 with two drawn.

Here are the live updates:

10.15 am: Pacquiao was unable to land a knockout punch on Floyd Mayweather during the 12th and final round of their megafight.

10.10 am: Mayweather gets aggressive once again in Round 11, trying to snatch opportunities from Pacquiao.

10.07 am: Bout takes a dramatic turn in Round 9. Pacquiao fights back brilliantly.

10.01 am: Mayweather getting the better of Pacquiao and scoring a few blows in Round 8.

9.58am: Very close round. Floyd dictating with his jab and boxing beautifully but Manny taking the fight when he sees an opportunity in Round 7.

9.55 am: Pacquiao pushing Mayweather to the edge and raining blows on him in Round 6.

9.52 am: In Round 5, Mayweather looks noticeably slower than he did in the opening rounds.

9:50 am: Pacquiao fights back with furious counter-punches against Mayweather in Round 4.

9.45 am: The third round sees Pacquiao on the attack. Mayweather backpedals.

9:35 am: Pacquiao under pressure after Round 2. Mayweather looking good after some powerful punches.

9.30 am: Mayweather in black and gold trunks, Pacquiao in yellow trunks with red trim. Floyd tags Manny with two rights early.

9.27 am: The fighters are ready, and the arena is packed. 

9.22 am: Floyd Mayweather makes his entry.

9.19 am: Manny Pacquiao walks to the ring.

9.00 am: First the Mexican anthem (for Cinco de Mayo), then the anthems of the Philippines and the United States.

8:55 am: Slight delay to the start of the bout. 

8.45 am: The big moment has arrived. Mayweather and Pacquiao ready to take the ring.

Las Vegas casinos were teeming with punters as the prospect of Pacquiao and Mayweather finally trading blows sent a crackle of anticipation rippling across the sporting world.

The long-awaited bout, which has been more than five years in the making, will rewrite the record books as the most lucrative fight of all time. Total revenue for the bout could reach an eye-watering $400 million, fueled by as many as three million purchases on pay-per-view television.

Paris Hilton waits for the bout to begin at the MGM Grand Arena. (Photo: AFP)

The breathtaking figures -- a possible $200 million payday for the unbeaten American and an estimated $100 million bonanza for Philippine icon Pacquiao -- have intensified the spotlight on a fight between two of the greatest pugilists of their generation.

As a taster for the main event at the MGM Grand Garden Arena, a raucous crowd of 11,500 turned out for Friday's weigh-in, as Pacquiao and Mayweather went nose-to-nose.

The few tickets that did go on sale for the bout itself were reportedly snapped up in one minute, with A-listers and high-rollers making up the vast majority of a 16,800 sell-out crowd, making the fight more akin to a nightout at the Oscars than two men attempting to pound the other to the canvas.

With just hours to go, dozens of tickets were still available on the resale website StubHub, ranging in price from $2,690 to $37,442 apiece.

The MGM Grand was heaving with fans hours before the fight Saturday.

Swanky starred restaurants and fast-food outlets were already packed, and promised to be even more crowded by fight time.

Lines were long to the betting windows at the sports book, where copies of the odds and proposition bets were being handed out so bettors could mull wagers as they waited.

Souvenir T-shirts and caps were flying off the shelves, although many of the big-fight shirts being worn were knockoffs, bought on the streets outside at less than half the $35 price of the official version.

Las Vegas tourism officials said occupancy for the city's 150,000 hotel rooms would approach 100 percent. Casinos were advertising red-carpet events hosted by hip-hop stars such as Puff Daddy and Snoop Dogg and pop star Justin Bieber -- a Mayweather fan and friend.

Clash of styles

Even if Saturday's bout doesn't measure up to Mayweather's claim of the "biggest fight in boxing history," it is set to be an intriguing clash of styles between men of contrasting personalities.

Pacquiao, 36, a two-term congressman with a music and film career, credits the grace of God for lifting him from poverty in his youth and later guiding him away from a life of excess that his ring success made possible.

"Pacman," who undoubtedly had the crowd on his side at the weigh-in, will go into the ring with all of the Philippines in his corner.

Streets will be empty on fight night -- Sunday morning in the Philippines -- as the nation of 100 million cheers its "National Fist." Guns often fall silent in the war-torn south of the country when the beloved Pacquiao is in action.

The brash Mayweather touts his status as a money-making machine and comes from a troubled past that includes jail time for one of a string of domestic violence incidents.

Mayweather, 47-0 with 26 knockouts, is a 2-1 favorite to add Pacquiao's World Boxing Organization world title to his own World Boxing Association and World Boxing Council belts.

Public opinion is with Pacquiao; boxing experts say Mayweather to triumph, most likely by 12-round decision. Mayweather, 38, is a supremely skilled boxer and potentially devastating counter-puncher, famed for his ability to hit without being hit.

Pacquiao, who owns a record of 57-5-2 with 38 knockouts, says he is content in his underdog role.

A winner of world titles in an unprecedented eight weight divisions, Pacquiao noted that he's beaten plenty of big foes, among them Oscar De La Hoya in 2008.

"No one thought I could beat Oscar, and I was the underdog then," said Pacquiao.