Mayweather masterful, but why no KO?

LAS VEGAS -- After 21 months out of the ring, nothing has changed.

Floyd Mayweather Jr. is still great.

Still crazy fast.

Still has sublime defense.

And he's still frustrating.

Mayweather put on a pure boxing clinic, pasting Juan Manuel Marquez in as comprehensive a performance as you will ever see in a unanimous decision victory before 13,116 (mostly Marquez fans on Mexican Independence Day weekend) on Saturday night at the MGM Grand Garden Arena.

There wasn't one minute of true competition in the fight, as Mayweather simply ran roughshod over the smaller man.

"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," he said. "And I know I'll get better."

That's the scary part. But the frustrating part was he missed a golden opportunity to close the show in style.

He left Marquez's face a swollen mess. Gave him a bloody nose, too. Oh, and he also deposited him on the canvas in the second round after landing a hybrid left hook/uppercut on Marquez's chin.

But the former five-division champion couldn't finish the smaller man, whom he hand-picked to fight instead of asking for an elite fighter in his own division (Miguel Cotto or Shane Mosley, for example).

"I dropped him with a punch I don't think he saw and when he got back up, he kept on fighting," said Mayweather, who gave up $600,000 to Marquez for not even attempting to get down to the contract weight of 144 pounds and showing up at 146 at Friday's weigh-in.

Said Marquez, "It was a very hard fight. He surprised me with the knockdown. He hurt me in that round, but not at any other time."

Yet for all of Mayweather's dominance, you never got the impression that he wanted to step on the gas and get Marquez out of there.

A knockout, which was clearly possible, would have been a big statement even if Marquez, a three-division champion and the reigning lightweight champ, was much smaller.

He had never been stopped and, more important, a knockout would have given Mayweather (40-0, 25 KOs) something Manny Pacquiao didn't have. Pacquiao, who ascended to the pound-for-pound throne when Mayweather retired, looms as Mayweather's mostly significant opponent down the road. The two of them are compared daily.

While Mayweather dominated a blown-up Marquez (50-5-1, 37 KOs), Pacquiao had escaped two life-and-death battles with him in a draw and one-point split decision win in featherweight and junior lightweight title bouts.

But instead of making a statement, Mayweather was getting in the work in workmanlike fashion, not the exciting, explosive way Pacquiao goes about his business.

"I just used what I had to use to beat him," he said. "I wanted to get in the rounds and I needed the work. I had to box smart the whole night. I am really glad to be back in boxing. I needed rounds."

When asked about the size disparity, Mayweather simply said, "He's a great small man, but don't forget, I came from a small weight class too."

Sure did. Several years ago.

As great a performance as it was, it was missing that exclamation point at the end of the sentence. That would have been the knockout.

Still, the CompuBox statistics were eye-catching in their landslide nature.

Mayweather landed 290 of 493 (59 percent) blows to Marquez's 69 of 583 (12 percent). Mayweather's jab was also dominant as he connected with 185 of 316 (59 percent) to Marquez's 21 of 288 (7 percent).

Now, keep in mind that Marquez's promoter, Oscar De La Hoya, had spent so much of the promotion talking about how Marquez needed to and would use his jab.

Yeah, right.

Marquez could do nothing against boxing's best, landing single digits in every round.

When it was over, it was surprising that the judges could find any rounds to give Marquez, but they apparently did. Judge Bert Clements had it a shutout, 120-107, but judges William Lerch (118-109) and Dave Moretti (119-108) found something to give Marquez.

ESPN.com had it a 120-107 shutout also. (The fight will be replayed next Saturday at 10 p.m. ET on HBO.)

What was amusing was listening to the largely pro-Marquez crowd scream with delight when Marquez would get off a slow four-combination and miss every single punch. It happened often.

By the end of the sixth round, referee Tony Weeks was concerned enough about the punches Marquez was taking that he visited the corner to see if Marquez wanted to continue.

The proud Mexican warrior did, of course, but it never got any better.

Tenth round? A 34-4 advantage for punches landed for Mayweather. And in the 11th it was 41-5.

Still, no serious effort for the knockout from Mayweather.

"Marquez is tough as nails," Mayweather explained. "He's a great little man. He was really hard to fight and he took some unbelievable shots."

Marquez, to no surprise, blamed the weight.

"I don't want to make excuses, but the weight was the problem," he said. "He's too fast. When I hit him he would laugh but I knew he felt my punches. We tried to work the speed but the difference was the weight. If I had three or four fights at this weight, I would do better. I did the best that I could do."

It wasn't nearly good enough.

But then again, he was good enough to make it to the final bell, and that's Mayweather's problem.

Dan Rafael is the boxing writer for ESPN.com.