International boxingSundayPacquiao     vs     Marquez    04:00 SS2 LAS VEGAS - LOS ANGELES - Saturday’s non-title welterweight bout between Manny Pacquiao and Juan Manuel Marquez has all the makings of a classic as the two fighters prepare to meet for a fourth and, almost certainly, final time in the ring.Their previous three encounters were gripping, all-action affairs between Filipino Pacquiao, probably the greatest offensive fighter of his generation, and Mexican Marquez, one of the best counter-punchers in recent memory.Adding further spice to the mix is the fact that both men have a lot to prove when they square up on Saturday at the MGM Grand Garden Arena for their heavily anticipated showdown.While the 33-year-old Pacquiao is eager to show his powers have not diminished with age after a below-par performance and a stunning upset in his last two bouts, Marquez is determined to set the record straight against the Filipino southpaw.Marquez has yet to beat Pacquiao, having lost twice and drawn once, but the 39-year-old Mexican firmly believes he was "robbed” of three wins simply because of the judges’ verdict."Everybody knows what happened in the last three fights,” Marquez (54-6-1, 39 KOs) told reporters while preparing for Saturday’s bout. "A lot of people feel I beat him."But I want to have my hand raised (in triumph). I want the judges to really look at what they’re doing and get it right this time.”When they last met, in November 2011, Pacquiao narrowly retained his WBO welterweight title with a controversial majority decision that was greeted by loud booing from disgruntled Marquez fans.Shortly after the Mexican had lifted his arms in apparent triumph, the Filipino earned the verdict from two of the three judges while the third ruled that the bout had ended level at 114-114."It’s hard when you’re fighting your rival and the three judges, too,” a fuming Marquez said at the time, before adding that he was contemplating retirement because of the outcome."I got robbed. Honestly I don’t know what I need to do to change the mind of the judges. We won with clearer punches. I am frustrated right now, very frustrated.”PACQUIAO VINDICATIONHowever that is all now in the past and Pacquiao is just as eager to win on Saturday, if only to vindicate his record against Marquez, a three-division world champion."He always claims he won the fights,” said Pacquiao, who has a career record of 54-4-2 with 38 knockouts. "So he needs to prove something."I am giving him a chance to prove he can win the fight because he thought he has won all three and he keeps talking about it."So it is very important to me, to win this fight, especially since Marquez really wanted this fight,” said the Filipino who lost his most recent fight on a hotly disputed split decision to American Timothy Bradley in Las Vegas in June.Pacquiao has won world titles in an unprecedented eight weight divisions and his trainer Freddie Roach has been delighted by his fighter’s preparation for Saturday’s bout."The fourth fight could be the same as the last three, but Manny’s hungrier now,” the bespectacled Roach said. "Manny is looking great in training. I like what I see."He is where I want him to be right now. His focus is where it has not been for some time. I don’t think Marquez has seen the best Manny yet.”Marquez and Pacquiao fought to a draw when they first met in May 2004 and the Mexican lost his WBC super-featherweight title to the Filipino in a controversial one-point split decision in March 2008.After Pacquiao won their most recent encounter 13 months ago in Las Vegas, Roach said Marquez had unquestionably proved to be the Filipino’s most difficult opponent."A 100 percent yes,” Roach told Reuters. "Manny loves it when guys come to him and they’re aggressive."Marquez is a counter-puncher and we’re probably going to have to go to him to make the fight happen. It’s a little harder for Manny to do that, so it’s the most difficult style for us.”