At stumps on a rain-curtailed second day, Sri Lanka were reduced to 24 for one with seamer Atul Singh dismissing rival skipper Kusal Mendis (6) cheaply.
With only 53 overs of play possible on second day, Indian bowlers will be hoping to take 19 wickets over the next two days in order to start the series on a winning note.
Indian batsmen added another 170 runs in 37 overs to their overnight total of 333 for two before deciding to declare the innings.
Samson (89, 162 balls, 14x4) was unlucky to miss out on a well deserved century as medium pacer Chamika Karunaratne induced an edge off the batsman that was pouched by 'keeper Mendis.
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Zol, however, got an able partner in Mumbai youngster Shreyash Iyer (65, 74 balls, 10x4) as the duo added 62 runs in only 13.2 overs as they upped the ante having lost out on a number of overs due to inclement weather. Zol missed out on a double hundred as Karunaratne got his second wicket with the batsmen nicking to keeper Mendis.
When the Lankans batted, their biggest hope Mendis was sent back promptly by seamer Atul who got a delivery to come back a shade into the right hander.
Brief Scores: India U-19 (1st Innings) 503/7 dec in 127 overs (Vijay Zol 173, Sanju Samson 89, Akhil Herwadkar 71, Shreyash Iyer 65, Shubham Khajuria 52, Chamika Karunaratne 4/94).
Sri Lanka U-19 (Ist Innings) 24/1 in 16 overs (Atul Singh 1/10).