BJJ Legend Buchecha Was 'Pretty Nervous' Before 'Amazing' 1st MMA Win

Brazilian Jiu-Jitsu legend Marcus "Buchecha" Almeida -- a 13x BJJ World Champ -- just put the whole MMA world on notice, after notching his 1st win with a crazy impressive performance at ONE Revolution.

31-year-old Buchecha submitted Anderson "Braddock" Silva in Singapore using a North-South choke only 2:55 seconds into the 1st round.

Only hours after the ONE Championship fight (the card was 🔥), TMZ Sports talked to the BJJ great about his foray into a new sport.

"Man, it was something amazing. It's hard to describe with some words. I had a great career in jiu-jitsu. I have done so much in this sport, and I feel like I didn't have anything left to prove. So I moved my challenge, and I'm just 31 years old."

Buchecha's been fighting for almost his entire life ... but this is a new sport. So, was he nervous?

"I was pretty nervous because I didn't know what to expect. It was first time. But I was feeling great. Before the fight I was really calm. Then going to the arena I was really tense. Then I got there and was calm again. It was kinda like a roller coaster."

Now, it's likely his future competitors who are nervous ... especially when they hear this.

"Anything that I do in my life, I put my passion in it mixed with hard work," Buchecha says.

"That's what I did my whole career in jiu-jitsu and it really worked out well for me. I will have the same mindset for MMA."

Speaking of impressive debuts ... we also talked to 32-year-old fighter, James Yang, and his mentor, MMA legend Demetrious Johnson.

Remember, we spoke to Yang before the fight about his experiences as a teenager in a Shaolin temple in rural China.

Yang beat Roel Rosauro by TKO in the 2nd round ... but how did Mighty Mouse think his protégé looked?

Check out the clip!