Lahiri, the highest world ranked player in the field, and winner of the Malaysian Open and Hero Indian Open this season, carded one-under 71 and at 13-under 275, he was tied for sixth.
Sweden's Henrik Norlander shot a course-record 10-under 62 to win by three strokes in a come-from-behind victory at 19-under 269 for the tournament on Sunday evening.
Korea's D.H. Lee, who started the day with a three-stroke cushion, got off to a fast start with birdies on two of the first three holes, but faded down the stretch with three bogeys to post a 1-under 71 and finish at 16-under 272 in a tie for second.
"It was probably a case of trying too hard," said Lahiri, who played his first 12 holes Sunday in 2 over before making three late birdies.
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"It was not the Sunday I expected. But I am happy with the fightback and progress in the Finals 25. I need to build on this week. I went out there and tried to push from the get-go, and I really didn't need to. I think it hit me like a bolt of lightning on the 12th green when I missed my putt for birdie. I was like, 'You know, what the heck? I just need to enjoy myself a little bit more.' I played well coming in, so I'm happy."
"The last stretch was fine and I am happy with the way I fought back and the birdie on 18th felt sweet. I am now looking forward to next week," said Lahiri, who has committed to playing the first three events on the Finals series and try and make enough money to earn the PGA Tour card for 2016.
Lahiri, named in International Team for Presidents Cup last week, collected a cheque for USD 34,750.