By CompuBox (photo by Chris Farina/Top Rank)

It isn't often that a champion plays second fiddle to his challenger (Pac Man’s a better than 3 ½-1 favorite) but WBC lightweight king David Diaz not only is accustomed to that role, he has thrived in it. 

He was losing badly to Jose Armando Santa Cruz in their fight for the vacant interim belt in August 2006 but two knockdowns in the 10th paved the way for an extraordinary title-winning comeback. Then, in his first defense, he was expected to drop the strap to Erik Morales and allow “El Terrible” to become the first Mexican four-division champ, but the gritty southpaw gutted out a close but unanimous decision. Now, on June 28 at Mandalay Bay in Las Vegas, Diaz (34-1-1, 17 KO) is a 3 ½-to-1 underdog to Filipino icon Manny Pacquiao (46-3-2, 35 KO), who will attempt to become just the fifth man to win titles in five divisions. If successful, “The Pac Man” will join Thomas Hearns, Sugar Ray Leonard, Oscar de la Hoya and the recently retired Floyd Mayweather Jr.

Mayweather's departure has elevated Pacquiao to the top of most pound-for-pound lists, and he got there because of his fast-twitch slam-bang style and his willingness to fight anyone, anytime and anywhere (a trait Mayweather sorely lacked in recent years).

Evidence of this can be found in his two most recent fights: A unanimous decision over Marco Antonio Barrera in October 2007 and a hotly disputed split nod over stylish boxer-puncher Juan Manuel Marquez. Both fights were rematches staged at Mandalay Bay, the site of this contest. 

Pacquiao's 11th round TKO of Barrera in November 2003 was his coming-out at the pound-for-pound level. Back then, the dynamic Pacquiao was a fistic storm who overwhelmed the heavily favored Barrera with sheer force. He averaged 76 punches per round (19 above the featherweight norm) and his 45 percent accuracy on power shots paved the way to a spectacular victory. In the rematch, a more well-rounded Pacquiao was less active (58 punches per round, on par with the junior lightweight average) but more balanced and efficient offensively. In the first fight Pacquiao was nearly 70-30 in favor of power punches while in the rematch he was 53-47 in favor of jabs, yet his success on power punches improved from 45 percent in 2003 to 54 in the rematch. Though they threw nearly the same number of jabs and power punches, Pacquiao more than doubled Barrera's connects (80-39 in jabs and 176-81 in power shots).

Just like before, Pacquiao followed his victories over Barrera with fights against Marquez, and both times the Filipino scored early knockdowns (three in the first round of fight one, one in the third round of the rematch) before struggling to razor-thin decisions (a draw in May 2004 and a split decision in March 2008). In each fight, Marquez landed more overall punches (10 more in the first, 15 more in the second) while throwing fewer (92 in the first, 108 in the second). Curiously, the trend in Pacquiao's ratio between the two fights is completely reversed, probably because Marquez's technical style forced the Filipino to think more. In the first bout, 64 percent of Pacquiao's punches were jabs but in the rematch he achieved almost perfect balance as he threw 314 jabs and 305 power shots. The accuracy of each, however, was still lopsided in favor of power punches (37 percent to 14 percent).

Though many believe that Marquez did enough to win the rematch, Pacquiao perhaps tipped the scales in his favor by out-landing the Mexican in three of the final four rounds, with Marquez earning a narrow 19-15 edge in the final stanza.

The statistics from these two bouts prove that trainer Freddie Roach's efforts to transform Pacquiao from a one-punch pony to a more complete fighter have been successful. Pacquiao has more tools in his toolbox, but will they be effective against the naturally bigger and stronger Diaz?

The ingredients that have made Diaz a champion are not as obvious as Pacquiao's. While the Filipino relies on brilliant hand and foot speed and shocking power, Diaz is physically strong, doggedly determined and blessed with massive reserves of stamina. In the final three rounds against Morales, Diaz enjoyed a 52-37 edge in overall connects (including a telling 48-27 bulge in power shots), plus he threw a fight-high 88 punches to Morales' 43 in the pivotal 12th. That trend was even more evident in his most recent fight against Ramon Montano as he landed 64 power shots to Montano's 28 in the final two rounds. In the 10th, Diaz threw 80 punches (his fourth highest total) to Montano's 60 (his lowest since round one's 55) and out-landed him 31-14. 

Unlike Pacquiao, Diaz virtually ignores the jab in favor of hooks, crosses and uppercuts. Against Morales, Diaz was an anemic 15 of 103 (15 percent) while he attempted just 45 jabs (landing 10) against Montano. The power punch-to-jab ratio was an incredible 82-18 against Morales and an astounding 94-6 against Montano. The reason why Diaz makes this work is because he throws lots of dynamite and doesn't get discouraged if they detonate less often than he likes. He threw 630 power punches to Morales' 326 – a difference of 25 per round. 

That, coupled with his non-stopaggression, projected an image of strength and aggression that may havepersuaded the judges to give Diaz enough of the close rounds to keep his belt.

Against Montano, the power gap was much smaller as Diaz threw 665 to Montano's 650. This time, it was Diaz's superior defense that enabled him to capture a majority decision that should have been unanimous. Though Montano threw 118 more punches (828-710), Diaz landed 77 more (270-193), including 88 more power shots (260-172). His ability to duck and weave under Montano's shots allowed Diaz to stay inside longer and pile up the numbers he needed to win.

Prediction: Had this been the Pacquiao that destroyed Morales in the rubber match, this fight would be easy to call. That Pacquiao would have torn through Diaz like a human tornado, but that version of “The Pac Man” doesn't exist anymore. At 29, Pacquiao is a couple of years past his positive peak and he is making his 135-pound debut against a career lightweight who has fought as high as 146 pounds (KO 2 Clifton Woods in October 2002). Pacquiao, who was briefly WBC flyweight champion in 1998, won't be able to bully Diaz physically and he'll have a difficult time breaking the champion mentally. Conversely, the 32-year-old Diaz is fighting about as well as he ever has and he'll be emotionally peaked against his most high-profile opponent yet. As Larry Merchant would say “these two aren't the unequals that many of us figured them to be.”

The million-dollar question is whether Diaz's intangibles will be able to trump Pacquiao's tangibles. My answer: No. All of Diaz's strengths are based on his being the larger man, but there is no dispute that Pacquiao is the far more talented fighter. Both men also tend to cut, but Diaz's scar tissue is even more fragile so don't be surprised if a gash leads to a TKO stoppage. The most likely scenario, however, is that Pacquiao will score a competitive but decisive unanimous decision.