Not only did he lose, he was embarrassed. He was the victim of a brutal, last second sixth-round knockout.
That's what it was literally. With one second left in the round, Marquez caught "Pac-Man" with a right hand to the jaw.
Pacquiao was knocked out cold, and as the rules state, you cannot be saved by the bell in any round.
When the pride of the Philippines did not wake up in between the sixth and seventh rounds, the referee and the doctor stopped the fight.
Marquez was awarded the victory and in the process got his payback for the previous three fights against Pacquiao.
This was the worst thing that could happen to Manny Pacquiao, and as a result, his future his now in doubt.
In my book, Pacquiao losing to Marquez is much bigger than Miguel Cotto's loss to Austin Trout the week before.
Here are the reasons why Pacquiao's loss was more damaging:
1. "Pac-Man" needed a victory to keep the hope for a potential Floyd Mayweather fight alive.
The undefeated WBA and WBC title holder had already defeated Juan Manuel Marquez back in 2009.
With the controversy surrounding the first three Pacquiao/Marquez encounters, this bout would have been the "legit" victory Pacquiao needed.
Despite Miguel Cotto losing almost two weeks ago, Mayweather has previously stated that he would grant the former world champion a rematch.
2. Even with the defeat at the hands of Austin Trout, there is still a very small chance that Cotto could get in the ring with "Canelo" Alvarez.
Floyd Mayweather has been hesitant to get in the ring with Manny Pacquiao, as evidenced by his demands which have derailed previous negotiations.
Alvarez is willing to take on any and all challengers despite their win-loss records.
3. Pacquiao's loss to Timothy Bradley in June was already a major setback.
In the eyes of Floyd Mayweather, the Filipino congressman had already proven he couldn't take down an undefeated fighter.
Regardless of how you feel about the authenticity of the decision of that fight, a loss is a loss and you have to take it with a grain of salt.
4. This was Pacquiao's first knockout loss in 13 years while Miguel Cotto has never been knocked out.
5. The 33-year-old Pacquiao was knocked out by a 39-year-old Marquez. The 32-year-old Miguel Cotto lost to a fighter that's still in his 20's and arguably a faster puncher.
The argument here, is that some believe that Pacquiao's power and speed has declined over his last few fights.
Miguel Cotto, on the other hand, has shown his ability to finish his fights while withstanding a great deal of punishment.
It'll be interesting to see where both fighters go from here.