By Jake Donovan

Some in-ring rivals grow to like each other, whether it’s a mutual respect or a genuine friendship. Others simply hate each other and look forward to the nights where they have the chance to inflict as much punishment as humanly and legally possible.

There’s probably good reason for Juan Manuel Marquez to not particularly care for Manny Pacquiao. Their three-fight rivalry has produced as many controversial decisions, a series where either fighter can be 3-0 just as easily as they can be 0-3.

Marquez believes he should have received the verdict in at least two of the contests, namely their third fight last November. The capacity crowd at the MGM Grand in Las Vegas loudly booed the final verdict, a majority decision in favor of Pacquiao.

Both fighters return to the venue for Part IV, which takes place December 8 on HBO Pay-Per-View. On that night, Pacquiao insists that nothing more will take place than two fighters there to perform for its paying audience.

“We are just doing our job in the ring. In the ring, we have to do our best to make all of the people happy,” Pacquiao (54-4-2, 38KO) states. “There is nothing personal between us. I never hate my opponent outside of the ring. We’re friends.”

One new entry into the series is that it is the first time in their eight-year rivalry in which no major title will be at stake when they meet in the ring.

Pacquiao was the lineal featherweight champ when he first faced Marquez (54-6-1, 39KO) – then a unified featherweight titlist, back in May ’04. Marquez was dropped three times in the opening round, but bravely battled all the way back to a split decision draw.

Their rematch four years later came with the vacant super featherweight crown at stake as well as Marquez’ alphabet belt, both of which was won by Pacquiao by split decision. A fourth round knockdown provided the narrow margin of victory.

There were no knockdowns in the third fight, the lone bout in which Marquez didn’t bring a title into the ring. He was the defending lineal lightweight king, but moved up to an agreed-upon catchweight for the Nov. ’11 bout, the highest grossing affair of the series.

The combination of the disputed outcome and the commercial success of the event laid the foundation for an eventual fourth fight. Neither fighter seemed to have it on their radar, but that changed after Pacquiao suffered a highly controversial points loss to Tim Bradley earlier this year. Rather than avenge his first official defeat in more than seven years, Pacquiao’s handlers saw fit to settle this old score instead.

So what happens if yet another close fight comes about – and worse, yet another disputed ending? Will the promotional driving force behind this event strive for part five?

“There’s always a possibility,” admits Hall of Fame promoter Bob Arum, whose Top Rank company has either co-promoted or served as lead promoter for every fight in the series. “Sugar Ray Robinson and Jake LaMotta fought six times.”

Pacquiao hopes that enough closure comes of December’s show to not have to travel down that road.

“I don’t know (about fighting Marquez a fifth time). I didn’t think there would be a fourth one,” Pacquiao admits.

Don’t mistake his hesitance for complacency, though.

“I’m not tired, I’m excited,” Pacquiao says of the rivalry, eight years and running – though hopefully coming to a screeching halt by December 9.

Jake Donovan is the Managing Editor of Boxingscene.com. Follow Jake on Twitter: @JakeNDaBox