MONTREAL — For rivals Georges St-Pierre and Nick Diaz, the fireworks were in the promotion. When it came time to fight, there really was little question of who the superior fighter was. In a one-sided drubbing, the UFC welterweight champion made his eighth straight successful title defense, earning a unanimous decision in the UFC 158 main event.All three judges scored it 50-45.I never took it personal, St-Pierre said of the pre-fight animosity between the two. He’s a veteran, he’s been fighting longer than me. He was in the UFC before me. I’m a big fan, he’s one of my favorite guys to watch. That’s one of the reasons I wanted to fight him. I knew he’d make a good fight.Diaz spent time trying to goad St-Pierre into a dogfight, but was mostly unsuccessful in doing so. He taunted him throughout the five-rounder, lowering his hands, fighting after the bell, and talking during the action.But after the fight was over, Diaz took a more sportsmanlike approach, shaking St-Pierre’s hand and then raising it in the air, admitting defeat.In his post-fight interview with Joe Rogan, the 29-year-old Diaz said he would consider the possibility of retirement. I think I’m going to have to figure out whether I want to keep doing this, he said before repeating the same sentiment later on.St-Pierre (24-2) set the tone of the fight almost immediately, taking Diaz down within the fight’s opening 20 seconds, and dominating him on the mat for the entire first round. While Diaz remained active looking for submissions and trying to work his way free, St-Pierre had no problems shutting him down and taking away his base so that he was stuck. At several points, he was able to land elbows and right hands, punctuating his control. That stretch seemed to slow down Diaz’s usually frenetic striking style, as his usual forward momentum would offer St-Pierre a trigger for takedowns. But in a sense, it didn’t matter. St-Pierre was going to take him down nearly at will. According to FightMetric, St-Pierre scored nine takedowns. Diaz (26-9, 1 no contest) said he was hoping to put together his punches somewhere around the third, but admitted that he felt flat as he struggled to mount offense. FightMetric stats showed St-Pierre out-landing Diaz by a cavernous 210-80 margin. Still, he credited Diaz for his gameness, and asked the crowd, which chanted expletives at Diaz several times during the fight, to give him the ovation he deserved.I didn’t want to fight in boxing range, St-Pierre said. He’s the best boxer in mixed martial arts. His jiu-jitsu is amazing. He has a very unusual scramble style. I don’t have training partners like that. When you fight a guy like this it’s almost impossible to get ready.I don’t want to make excuses, Diaz said, I came out a little flat. I just want to thank GSP for giving me the credit I think I deserve.And like that, the sport’s biggest grudge faded away. And so, too, might have one of its big stars.