The American, who recorded victory at Augusta in 2012, holds a three-shot lead over his nearest rival after carding a 68 to move to seven-under-par for the tournament.
"You're playing the best golf course in the world. So when you're out here, it's a little bit different. The emotions are different because I'm trying to get the green jacket again," Watson told reporters. "I had it, there's so much you're doing when you're defending champ, and my mind can't handle it.
"I'm coming back with a different mindset, full of energy. I haven't had any media because nobody cares about the guy a couple of years ago. So it's been good."
Watson has won just one tournament since achieving success in The Masters two years ago.