Sandeep conceded just 25 runs in his 11 overs to account for seven Saurashtra batsmen after Punjab invited the visitors to bat at the PCA stadium.
Punjab though could not take complete control over the match as they lost five wickets in reply, to reach 125 for five at close.
Wicket-keeper Uday Kaul (4) and Bipul Sharma (13) were at the crease when day's play ended with Punjab leading by 35 runs.
Earlier, Sandeep ripped apart the Saurashtra middle order after Manpreet Gony drew the first blood in form of opener Chirag Pathak (8).
Except for Bhushan Chauhan (29) and Sagar Jogiyani (41) none of the Saurashtra batsmen could reach the double-digit mark.
The duo added 61 runs for the second wicket before Sandeep triggered a batting collapse. Saurashtra lost last eight wickets for just 17 runs.
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Sandeep began the mayhem by trapping Chauhan and after that within 11 overs, Saurashtra were all out.
For Punjab, Jiwanjot Singh was yet again among runs as he scored 61 off 128 balls. Jiwanjot and his fellow opener Karan Goel (26) added 70 runs for the first wicket.
However, the Pujab middle-order could not take advantage of the good start and from 70 for 1 they were reduced to 125 for five at the end of the day.
Siddharth Trivedi (2/37) and Sandip Maniyar (2/8) shared four wickets between them while Jaydev Unadkat took one wicket.
Brief Scores:
Saurashtra 1st innings: 90 all out in 27.1 overs.(S Jogiyani 41; Sandeep Sharma 7/25)
Punjab 1st innings: 125 for five in 52 overs. (Jiwanjot Singh 61; S Maniyar 2/8).