Marcos Maidana confident of upset

The Argentine, 31, went close to upsetting Mayweather in May, losing by a majority decision in Las Vegas.

Mayweather (46-0) gave Maidana a rematch, putting his undefeated record and WBA and WBC welterweight belts on the line.

After a weigh-in at the MGM Grand, Maidana (35-4) told reporters the result would be different this time.

"The first fight was very close," he said.

"I made a couple of errors and I will rectify those and we will see a different result.

"My punches weren't that accurate, that is why I did not win the fight but this time they are going to be."

As the weigh-in ended without incident, Mayweather is wary of Maidana.

The 37-year-old American, who plans to retire in 2015, said he would perform better.

"It was a good competitive fight. I won, you live, you learn what else can I say," he said.

"The only thing you want to do is make things better always.

"I can make adjustments, that's happened before in my career. No-one is perfect, I was trying to be a perfectionist but no one is perfect."