Singh opened with an early goal in the 11th minute and then added two more goals in the second half as Royal Wahingdoh FC beat the Goans in their last home match of the season.
The other goal was scored by Densill Theobald in the 60th minute.
While Douhou Pierre netted the first equaliser in the 56th minute, Darryl Duffy scored the consolation goal for Salgaogar in the 83rd minutes of the match.
With today's win, Royal Wahingdoh have 30 points from 18 matches and were placed two points behind table toppers Mohun Bagan FC and two points ahead of third place Bengaluru FC.
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Jackichand Singh and Seityasen Singh combined well at the front even as Theobald exploited the midfield by breaking the visitors' defence.
Returning from the lemon break, Salgaocar took hardly 10 minutes to find their first goal to equalise. Pierre found the net from a freekick just outside the box when the Ivory Coast midfielder was fouled by Royal's Reagan Singh.
Upping their ante, Densil Theobald found the net when his right footer was too strong for Paul to react three minutes later, as the 16,000 strong-home crowd cheered.
In the 63rd minute, a Gurjinder Kumar shot went wide after which Wahingdoh returned to score their third goal, the second from Seityasen in the 68th minute.