Sharma, who broke the course round on Friday with an eight-under-par 64, saw his challenge disintegrate as he registered a three-over 75 which contained three double-bogeys, three further dropped shots and six birdies.
Shubhankar started the fourth round with two birdies through four holes.
Englishman Matt Wallace (69-70-70-68) defeated compatriot Andrew Johnston (72-66-73-66) in a playoff to lift the trophy after the two were tied at the top with matching totals of 11-under-277 at the end of the regulation 72 holes.
Shubhankar Sharma was unable to keep pace with Wallace as he slipped from a share of first to seventh with a three-over 75, posting a trio of double-bogeys in a frustrating round.
Argentine Emiliano Grillo, who had an overnight four-stroke lead at the top over Shubhankar, had a day to forget as he signed for a six-over 78.
Sihwan Kim of the United States adopted an aggressive, yet calculated approach to card a 72. This could not be anticipated when Wallace jumped to 12-under after the 10th hole to lead Johnston by three shots.
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Beckham is entering the final year of his rookie contract and is seeking a long-term extension worth around $100 million. According to ESPN, the Giants are aware of the video, and gave the following comment in response.
"I feel awesome. It was a hard week and a hard golf course but you can't be off your game", said Wallace after bagging his second European Tour title. In what must rank as a disappointment for home fans, only eight Indians made the cut on the lengthened - and testing - course at their national Open, and of those that survived, seven - including 2015 victor Anirban Lahiri (T32, 75) - went over par as conditions continued to test resolve, ability and skill. It was a mixed bag as everything happened.
In the play-off, after Johnston had laid up short of the lake, Wallace played a bold shot to the back of the green, which rolled 15 feet from the flag. I didn't hit many great iron shots on the back nine but I knew where I stood. I'm very pleased with the birdie at the last, which allowed me to grab a share of the lead. I'm looking forward to tomorrow. In the end, I just want to play good golf. I think hes going to do really well. It's the second week in the row I'm in the leading group.
The tees were moved back on certain holes and the pins were quite challenging and I am keen to see if it is going to be the same on Sunday and how the players adjust to it.
"It was hard. I played really nice and I just said as we walked off, the bogeys I made I hit kind of good shots".
Other Indians: 218: Ajeetesh Sandhu (68, 76, 74); 220: Jyoti Randhawa (72, 72, 76), Anirban Lahiri (72, 73, 75); 221: Khalin Joshi (72, 68, 81); 223: Kshitij Naveed Kaul (70, 76, 77), Karandeep Kochhar (75, 72, 76); 226: Udayan Mane (72, 75, 79).