With the lethal combination of blinding speed and devastating punches, Manny Pacquiao cemented his status as boxing's best pound-for-pound fighter and the Philippines' greatest boxer of all time.

Pacquiao hammered David Diaz with a crushing left hook in the ninth round to knock out the defending champion and wrest the WBC lightweight crown in their title match dubbed Lethal Combination in Las Vegas.

In annexing his second world title in four months, Pacquiao became the first Asian boxer to win major world titles in four weight divisions and the only Filipino to win the lightweight belt. Just last March, Pacquiao also snared the super featherweight crown from bitter Mexican rival Juan Manuel Marquez via a split decision.

Like a thoroughbred raring to race, Pacquiao bolted out of his corner right at the opening bell and pummeled Diaz with crisp combinations and stinging right jabs. Pacquiao might as well have been a wayward truck: "Did anybody get the number off that truck?," Diaz said in jest at the post-fight conference.

Clearly, David Diaz didn't see what was coming. Despite a valiant effort to stay on his feet after absorbing Pacquiao's punishment in the early rounds, Diaz crumbled down when Pacquiao flicked a right jab and followed it with a short, powerful left hook that unscrewed the champ's jaw. Referee Vic Drakulich did not even bother to count and waived Diaz out as soon as his lips kissed the canvas.

The Filipino boxing icon displayed a masterful performance by sticking to the gameplan devised by his American trainer Freddie Roach, who stressed that Pacquiao must run circles around Diaz and use speed to move away after delivering his combinations. Pacquiao obliged with the zeal of a convert and followed his master's wishes.

Diaz's reputation of carving out come-from-behind victories preceded him, leading fight observers to think that his gameplan was to exhaust Pacquiao until the Filipino punched himself out and deliver the coup-de-grace in the late rounds. But just when it seemed that Diaz was ready to follow the script of his dramatic fights, Pacquiao delivered the finale of his own by stopping Diaz at the 2:24 mark of the ninth round of the scheduled 12-rounder.

Asked what made the difference in the fight, Diaz replied: “It was his speed. It was all about his speed. He boxed more than I thought he would”. In a candid admission on live TV, Diaz let out an expletive in jest to demonstrate his admiration of Pacquiao: "I didn't know he was that fast. He was f****** good!"

Pacquiao's sensational knockout of Diaz erased doubts about his ability to carry his speed and power in the 135-lb division, where erstwhile 130-lb mainstays like Marquez and Venezuelan knock-out artist Edwin Valero are now eyeing to face Pacquiao.

Marquez moved up in weight to possibly force a third showdown with Pacquiao at 135 if he gets past Joel Casamayor on September 13. Pacquiao's promoter, Bob Arum, hinted at a possible face-off with Valero in November.

In another possible mega-buck fight whetting the appetite of boxing fans, Roach and Arum also made known their desire for Pacquiao to fight Ricky 'The Hitman' Hatton, the extremely popular British fighter who Pacquiao might fight at 140.

Pacquiao's historic conquest of the lightweight division elevated him to a higher stage than the other great Filipino fighter, Gabriel 'Flash' Elorde, failed to reach. Elorde was the junior lightweight champion for seven years in the 1960s but was twice denied by lightweight champ Carlos Ortiz via knockouts in their two fights.

Pacquiao has previously won world titles at flyweight, super-bantamweight and super-featherweight divisions to virtually enshrine himself as the most successful Filipino prizefighter.