Defending champions Punjab were shocked by Manipur 2-1 in the quarter-final Group A league opener in the 63rd National Football championship, for the Santosh Trophy, at the Jawaharlal Nehru Stadium, in Chennai on Tuesday.
Punjab took the lead in the 27th minute when an unmarked Balwant Singh headed home a Boy Singh cross from the left.
But former champions Manipur equalised within two minutes when a free-kick by M Raju was deflected by Sarabjit Singh into his own goal.
Punjab, playing their first match in the tournament, were stunned by the goal and Manipur grew from strength to strength.
After the change of ends Manipur applied more pressure on the Punjab defence and were rewarded in the 48th minute when Subhas Singh found the net from close range.
Reisangmi Vashum left Anwar Ali and Ravinder Singh chasing shadows and took a shot towards goal. Goalkeeper Karanjit Singh blocked the effort partially but Subhas was close at hand to knock in the rebound.
Manipur, who played three matches in the qualifying stage of the tournament, looked in better shape and controlled proceedings much better than their opponents.
With West Bengal and Tamil Nadu also in their group, Punjab have a difficult task of progressing from the quarter-final stage.
However, Punjab coach Jagbir Singh was not unduly worried with the defeat since they had also lost their first match in last year's tournament before going on to lift the title.