Last year, former NFL great Herschel Walker announced that at age 47 he was joining the ranks of the Mixed Martial Arts (MMA) world. Walker signed a contract with MMA league Strikeforce and made his debut on Showtime over the weekend.

He defeated Hungary's Greg Nagy by technical knockout in the third round. After Walker forced Nagy in to the cage, Walker took him to the ground and threw relentless punches until referee Troy Waugh stopped the fight.

"The experience was exciting," Walker said after the fight. "This is the hardest thing I've ever done."

When Walker announced his new venture in MMA, he maintained that he was doing it to be able to participate in a competitive sport – it wasn't about the money. He stood firm in his statement and donated all of his winnings to charity.

"I feel good, but I didn't do many things right, and I still have a lot to learn,'' Walker said in a statement. "The experience itself was exciting and I thank my opponent for fighting me. It's tough to fight an old man. This is the hardest thing I've ever done.

"I thought I'd be more nervous. I'm an MMA fighter now. I earned a little bit of a stripe tonight. This is one of my biggest athletic achievements ever."

Check out the fight: