Christopher scored twice in the first half while Ram Malik and Odafa Okolie increased Mohun Bagan's advantage in the second half with United goalkeeper Ishan Debnath being taken to the hospital after suffering a serious injury towards the end of the game.
The result ends Mohun Bagan's five-match winless streak and moves them up to seventh in the table while United suffered their third defeat of this campaign.
It was an even contest in the early stages with ball possession similar and hardly any clear cut chances. The first real attempt on goal came from Mohun Bagan's Manish Bhargav, who cut in from the left flank and rattled the bar with a right-footed effort.
At the other United SC's Syrian defender Hassan Moustafa failed to hit the target despite getting a free header following an Eric Brown freekick.
Mohun Bagan went in front in the 20th minute when Christopher was given the time and space to shoot from outside the box and the Nigerian's shot gave Debnath no chance. It was Mohun Bagan's first goal in four matches and made Christopher an instant hero among the supporters.
United coach Eelco Schattorie made a double change in the first half itself but his side couldn't come back into the match and found themselves 2-0 down just before the interval.
Odafa held up the ball well before playing Christopher clean through on goal and the debutant rounded Debnath before finding the back of the net.
Mohun Bagan's new signing from Peerless couldn't have wished for a better debut and things got better for them at the start of the second period as young Ram Malik netted the third.
Some nice interplay between Odafa and Katsumi Yusa saw the latter set up Malik and the starlet slotted home to virtually seal the points.
--IANS (Posted on 06-12-2013)