Floyd Mayweather Arrives In Mexico City For Gotti III Fight, Serenaded By Mariachi

Floyd Mayweather has arrived in Mexico City ahead of his exhibition with John Gotti III ... and he's already immersed himself in the local culture -- dancing along to mariachi!!

The 47-year-old boxer's private jet touched down in the city on Monday to face the grandson of John Gotti for the second time this weekend ... and as soon as he got to his hotel, he was greeted with some sweet tunes.

A mariachi band crooned as Floyd danced around ... and he was clearly pleased with the performance, waving his arms around on beat with the song.

The undefeated boxer looks loose and care-free as fight night quickly approaches ... but what about his opponent??

Well, we spoke with Gotti III to get his thoughts on the rematch ... and he admitted the hoopla of the first fight took him by surprise -- but he is more locked in this time.

"Now I know what to expect. I didn't really know what to expect the first time around," Gotti III said ... adding, "I mentally prepared myself for the last year, and I've been training for this moment. So, you know, all I can do is show up and I'm going to fight as hard as I can fight."

It all goes down this Saturday in Mexico City ... and hopefully things end peacefully, unlike last time .