Pacquiao entered the year as one of the best pound-for-pound fighters in the world. He had won 15 matches in a row and built up a career record of 54-3-2.
Of course, arguments over drug tests and the split of revenue prevented this fight from occurring. This meant that Pacquiao had to fill up his schedule with lesser opponents.
Unfortunately for him, they turned out to be anything but.
In June, Pacquiao lost in a controversial decision to Timothy Bradley. According to Dan Rafael of ESPN, WBO review gave the decision to the Pacman, but it still stood as a loss in the record books.
Bradley was able to leave with the WBO welterweight title, and Pacquiao was forced to recover.
Even after this loss, it was easy for the former champ to continue his path and remain as one of the top fighters in the world. That was at least until the fourth fight against Marquez.
Dinamita had been a nuisance to Pacquiao, but never officially won a match in the rivalry. That ended with a sixth-round knockout on Saturday night.
Pacquiao has now lost two matches in a row, one of which by a decisive knockout. This effectively ends his reign as an elite fighter and limits his options going forward.
The dream of facing Mayweather is over. There is no reason for one of the top fighters in history to risk his legacy against a fighter that has not earned it in recent matches.
His only option going forward might be yet another rematch with Marquez. When asked about a potential Pacquiao-Marquez 5, he responded with this after the match (via ESPN):
Why not? Yes, it's a good fight. I was just starting to feel confident because I thought I got him. If they give us a chance, we'll fight again. I'm gonna take a rest and then I am coming back to fight.
If Marquez does not agree to this, we might have seen the last of Pacman on the big stage.
Of course, it would not make sense for Saturday's winner to agree to another match. He already vindicated himself in this rivalry after coming close so many times.
Marquez believed he had won three times against Pacquiao and wanted to do everything in his power to avoid another decision. Even though he was bloody and probably close to losing, the veteran came through with a great right hand and knocked out his competition.
This instantly jumps Marquez from a good fighter to one of the best of this generation. His only losses since 2000 were to Mayweather and Pacquiao, and now he has avenged one of those competitors. The other loss is nothing to be ashamed about.
The knockout was the definitive end to this rivalry that he was hoping for, and it completely changes the way his career is viewed.
Almost all fights have a winner and a loser, but the difference between the two afterwards is not always great. This is as different as they come, as it changes the legacy of each competitor.
This will remain until we possibly see a fifth match between the two warriors.