Larry and Josh Nelson had a one-shot lead in the scramble format over David Duval and his stepson, Deano Karavites.
The two-day tournament, held at ChampionsGate Golf Resort, is limited to major champions and their sons. The tournament again made an exception for Arnold Palmer, who played with 20-year-old grandson Sam Saunders. They were among four teams tied at 62, with Saunders, who plays at Clemson, playing a big role in their 10 birdies.
Bernhard and Stefan Langer, the two-time defending champions, opened with a 64.
Josh Nelson, a self-described entrepreneur who plays off a plus-2 handicap, hit 2-iron from 223 yards to 18 feet to set up an eagle on the 510-yard 16th hole, then knocked a 6-iron to 8 feet to set up another eagle at the 528-yard 18th. Josh sank both of the eagle putts.
'It's our best round here in six tries,' said Larry Nelson, 60, who won this even in 2004 with his oldest son, Drew. 'He (Josh) is playing the best he's ever played coming in. It's fun to watch.'
The Nelsons played the final 11 holes in 10 under.
Nelson is trying to become the second player in the 13-year history of the Father-Son Challenge to win with two different sons. Raymond Floyd won three times with son Raymond Jr. and twice with son Robert.
Josh Nelson laughed when asked if his older brother gives him a hard time about not having yet won at the Father-Son.
'He knows that he's done this for a living (played professionally) and I haven't,' Josh said of Drew. 'My question to him is why he's only won one. No, he's good about it. Obviously, I'd like to win one just for the experience with my dad, and the memories.'
Duval, 36, whose 13 career PGA Tour victories include the 2001 British Open, returned to competition in September after a seven-month break while his wife gave birth to their second child. Although he hadn't hit a ball for nearly two weeks before arriving in Orlando, he said he was pleased with how he struck the ball, and he putted exceptionally well. The Duval duo birdied their first three holes and finished strong, closing with four straight birdies.
'That was incredible,' Duval said. 'We played quite well. I'm so proud of Deano and how he played and how he handled himself. He got up on (No.) 1, fired it down the middle, and off we went. He should hold his head high.'
The 18-team field had one other exception to the father-son rule -- former Masters and U.S. Open champion Fuzzy Zoeller played with his daughter, Gretchen. They shot 65.