The home favourite was lucky to pip Prom to the title after he had ended regulation play with his week`s highest score of one-over par 73 at the Delhi Golf Club. An upset seemed to be on the cards when Prom overcame a three-shot deficit to take a share of the lead with Lahiri from the 16th hole in regulation play.
The Thai closed with a 70 for a 14-under-par 274 total and headed to the play-off brimming with confidence.
Prom`s tee shot at the first play-off hole, however, found the bushes on the right.
Lahiri, meanwhile, had a good tee shot and managed to reach the green in three. He came within three feet for his birdie putt. Prom then decided to pick up his ball and concede defeat. "My consolations go out to Scott Barr and Prom as they played brilliantly today and I`m just fortunate that I managed to pull it off," said Lahiri.
"I`m disappointed with the way I hit the ball as I`ve hit it much better the last three days. I found two bushes today which I had to chip out and that was something I haven`t done all week. I also dropped five shots which is not something you can get away with at this golf course, especially on the final day," added the Indian.
Prom remained upbeat despite narrowly missing out on his second Asian Tour title. "I`m very happy with my two-week stay in India despite losing in the play-off today. When I got out there for the play-off, I thought I could win it," said Prom.
"I tried to put my ball onto the fairway with my tee shot but it found the bushes. I managed to hit all the fairways during regulation play but unfortunately I had to miss my only one on the play-off today," added the Thai.
Australia`s Scott Barr looked set to for a grandstand finish until a disastrous triple-bogey six on the 17th hole put paid to any hopes of a maiden win.
The Singapore-based Australian had to settle for third place on 275 while Ben Fox of the United States closed with a 278 to take fourth place with Bangladesh`s Siddikur a further shot back in fifth place on 280.
The SAIL-SBI Open is the second of the four events scheduled to be played in India on the Asian Tour this season.