It wasn't. Still, Mayweather won a comfortable decision by scores of 118-109, 120-107, 119-108 in a non-title welterweight matchup Saturday before a crowd of 13,116 at MGM Grand Garden Arena.
"I've been off for two years so I felt like it took me a couple rounds to really know I was back in the ring again. I know I'll get better," Mayweather said. "Marquez is as tough as nails."
Marquez, regarded as one of the two best pound-for-pound fighters coming into the bout, was significantly undersized. A featherweight for most of his 16-year career, he'd never fought above 135 pounds. The bout was supposed to be at 144 pounds, but instead the weight limit was changed before Friday's weigh-in because Mayweather was over. He paid a $600,000 penalty, or $300,000 per pound, to the Nevada Boxing Commission. Marquez's base salary for the fight was $2 million.
Although the Mexican hit the canvas early, it appeared that he had more trouble with Mayweather's speed than power. By the later rounds, as the former welterweight champion began to potshot Marquez with hooks, he was able to handle them better.
"He's a great little man. He was really hard to fight and he kept taking some unbelievable shots," Mayweather said. "When I dropped him with that shot, which I don' t think he saw, he got back up and kept on fighting."
This was the first fight for Mayweather (40-0, 25 KOs) since his December 2007 knockout win of then-undefeated Ricky Hatton.
Marquez (50-5-1, 37 KOs) knocked out Juan Diaz in his last bout seven months ago at lightweight, where he was the lineal champion.
"It was a very hard fight. He surprised me with the first knockdown. He hurt me in that round but not any other time," Marquez said. "I don't want to make any excuses, but the weight was the problem.
"He's too fast. When I hit him he would laugh but I knew he felt my punches. I tried to work the speed, but the difference was the weight. If I had three or four fights at this weight I would've done better."
According to CompuBox punchstat estimates, Marquez only landed 12% of his 583 punches, or 69. Mayweather threw 493 but scored at 59% accuracy, or 290 punches. He also worked well behind his jab, scoring 185 times with it.
"I had my jab working," Mayweather said. "I was really happy with my jab.
"I think he brought his best out tonight. He's a great small man. Don't forget, I came from a small weight class, too," said Mayweather, who began his career at junior lightweight (130). "I know when you're in front of a great fighter."