The visitors got their first shock when Sushil Kumar headed a volley from Jacob to secure lead in the third minute of the game.
Caught off guard on several occasions, the hosts missed few chances, even as, Sushil opened the second half with his second goal in the 49th minute.
Three minutes later, Friday sealed the visitor's fate by scoring the third goal for the home team.
Pailan Arrows reduced the deficit through Dhanpal Ganeshan in the 65th minute, but the goal proved nothing more than a consolation.
Pailan's Coach Arthur Papas blamed his boys' slackness on the field for the defeat.
"You can't concede a goal within five minutes of the game. Your boys have to get themselves switched on right from the moment the whistle blows," Papas said, adding that his boys only showed some aggression after conceding three goals.
Papas' counterpart, Desmond Bulpin said his team played well today but conceded his boys lack calmness while controlling the ball.
Lajong now has 10 points from eight games while Pailan is still at 11 points from an equal number matches.
Lajong play their next game against East Bengal at home. Pailan Arrows on the other hand face ONGC.
Lajong's North Korean defender Minchol Son was awarded man of the match.
