The world number two carded a round of 62, which included a 35-foot birdie on the 16th, to earn a three-shot lead in Orlando, and he admitted that his form with the putter was pleasing.
"Obviously I'm really thrilled with the start," Scott told reporters. "It's maybe a little surprising. I don't know where it came from, but the putter certainly got hot.
"I made a lot of putts today, and a lot of putts from considerable length."
Scott is looking for his 11th win on the PGA Tour.