Lahiri was five strokes off the lead on a day when conditions were not easy and leader, Sergio Garcia (65) avoided an alligator.
On a tough but typically windy day at PGA National course, Lahiri opened sedately with two pars and then found his first birdie on the par-5 third. But he dropped shots on sixth and ninth to turn in one-over.
A third bogey on 14th meant he was staring at a disappointing two-over, but the gutsy Indian, who won two titles on European Tour in 2015, including the Hero Indian Open, fought back with excellent birdies on 17th and 18th to close at even par.
On his bogey on sixth, Lahiri said, "I hit a bad tee shot but I would still say it was a good bogey because it could have been worse. What gave me good feel at the end was the par-5 18th, where I made a solid four. I hit a good tee shot and then followed with a good up and down from just over the back (of the green)."
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Garcia made an eagle but also avoided an alligator on Thursday. He holed out with an 8-iron from 142 yards into the wind on the second hole for an eagle, and he narrowly missed an eagle putt on the 18th hole at PGA National. The Spaniard shared the lead with Michael Thompson, the 2013 winner, who also birdied the last hole. The duo was one shot ahead of Rickie Fowler and William McGirt.
The exciting but dangerous moment for Garcia was on the par-4 sixth hole, where he made his lone bogey. His tee shot found the water left of the fairway but it was shallow enough for him to roll up his pants and try to play it out to the fairway. But he also needed to look over his shoulder because an alligator was on the island.
"I was more worried about the alligator that was on the other side of the island than getting out of the water," Garcia said.
Phil Mickelson extended his good play from a runner-up finish at Pebble Beach and shot 69, among 10 players who managed to break par in the morning. Rory McIlroy signed for a two-over 72, while the day also saw Alex Cejka make an ace at the par-3 17th.