The 28-year-old Lahiri, whose sole top-10 in 2016 came in the European/Asian Tour event, the Hero Indian Open, where he finished second, shot 68 in the final round in Texas to finish with a total of nine-under 271 at the Colonial Country Club.
The finish here bettered his previous best this 2015-16 season of tied 21st at CIMB Classic in Malaysia, which is PGA Tour's only stop in Asia.
At the top Jordan Spieth (65) reminded of his 'Masters meltdown' by a fan at the turn, raised the bar on the back nine with six birdies to grab the title, his first in his home state of Texas. He ended with 17-under and three clear of Harris English (68).
Lahiri, who admitted he was disappointed that he could not keep the gap smaller than five shots after three rounds, kept his word of going all out early in the final round.
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Lahiri had three birdies and no bogeys in his front nine and then added two more on 10th and 11th. At one stage at 12-under, he rose to 12-under and was a mere two shots behind the then leader, Harris English.
He was then faced with a 15-footer for a bogey but he missed that and ended with a double.