Man-of-the-Match Ranty Martins' double strike guided Federation Cup champions Dempo to a 2-0 victory over Vasco and closer to the National Football League title at the Nehru stadium in Margao, Goa, on Thursday.
Vasco started on a promising note and had the first look at their rival's goal after Anthony Pereira's scorching drive from inside the box hit the bar, off Kamal Thapa's long pass.
They were again unlucky in not finding the target as Satish Minz's powerful drive again hit the cross bar.
Dempo, who took some time to settle down, surged ahead in the 25th minute.
On receiving a pass from Riston Rodrigues, Martins directed the ball towards the target but his shot deflected off a rival defender and rolled in before another defender, Kamal Thapa, tried to put it out.
Minutes later, Martins scored again when he headed home a cross by Johnny D'Cruz, a move initiated by Riston Rodrigues.
With this goal, Martins took his individual tally to 17 goals.
The second half was mostly confined to midfield and Martins had a chance to score a hat-trick but goalkeeper Virender Singh came to Vasco's rescue as he parried Ranty's shot to safety.
Vasco retaliated and came close to scoring but Sushant Mathews' shot was put out by 'keeper Satish Kumar.
With this win, Dempo, who are second in the points table, a point behind leaders Sporting Clube de Goa, took their tally to 44 points from 20 matches and still have two matches to play.
Dempo's crucial match against East Bengal at Kolkata on May 16 will virtually decide their fate before they play their last match against Tollygunge.
However, with today's defeat, Vasco confirmed relegation to the second division along with Tollygunge and SBT.
Vasco are currently placed 10th with 17 points from 21 matches.