Nigerian star Jackson struck in the 35th minute to give a 1-0 lead to R K Steel, Siwan.
Raju Roy increased the lead (2-0) in the 58th minute for R K Steel, while Bishwajeet Ghosh of Army junior, Lucknow, scored in the 62nd minute to reduce the margin to 2-1.
However, Tanmoy Pal struck in the 67th minute to extend the lead for R.K. Steel, Siwan.
Earlier in the day, Raj Milk drew with Punjab Police (2-2) in their second group league match.
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In the second half, Emi Amanuel scored the second goal in 71st minute for Raj Milk.
Punjab police, however, came roaring back as Sarabjit Singh struck in the 86th minute to reduce the margin to 2-1.
Ranjit Singh scored the equliser in the extra time 92nd minute at the match between Punjab Police and Raj Milks ended at 2-2.