Salgaocar's went down 1-4 to Mohammedan Sporting and were relegaed to the second division of the National Football League.
Salgaocar, who won the title in 1997 completed their league engagements with 12 points from 17 matches, and finished at the bottom.
Mohammedan Sporting aggregated 17 points from 17 matches.
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In a battle of cellar teams, at the Nehru stadium in Fatorda, Goa, on Sunday, Mohammedan Sporting, who needed only a draw to avoid relegation, started positively and surged ahead in the 14th minute.
Patrick Okanji accepted a pass inside the box from Mukhter, dodged past a couple of defenders and 'keeper Sangram Mukherjee before sloting the ball into the net to put Sporting 1-0 up at half-time.
Gley Rodrigues then doubled the lead for Sporting in the 55th minute, when he slammed the ball home after Patrick split the defence with a through pass.
Salgaocar could have easily scored a couple of goals in the first half but Jyothi Kumar and Ashim Biswas failed to direct their shots on target when presented with chances.
Substitute Satyajit Bose then finished off Salgaocar when he headed home a cross from the right
by Mohammed Mukhter in the 70th minute.
Gley Rodrigues rounded off the tally in the 82nd minute to give Sporting an emphatic win.
Fabio Passo scored a consolation goal for Salgaocar in the 87th minute through a penalty after Satyajit Bose tripped Aseem K inside the box.
Patrick Okanji, who scored a brace, got the man of the match award.
Salgaocar coach Savio Medeira was disappointed with his team's performance.
"The defence left lot of gaps after we tried to pressurise the rival fort as they socred two goals to seal our fate. We will try to come back like Dempo and Churchill who were earlier relegated to the second division league of the NFL," he said.
Sporting coach Subhas Bhowmick was a happy man.
"I just can't express my feelings," said Bhowmick. "We both were sailing in the same boat."