After Unadkat's 5/70 saw Subramanium Badrinath's side being bowled out in just 50.4 overs, Saurashtra batted cautiously to end the day at 70 for one in 30 overs.
Test specialist Cheteshwar Pujara Pujara looked in good touch as he remained unbeaten on 45 from 71 balls with nine boundaries to his credit.
With the wicket easing out, Pujara looks set for a long haul and Saurashtra will be aiming to outbat the opposition. Giving Pujara company is the other opener Sagar Jogiyani, who consumed 87 balls to remain undefeated on 19.
Within the first 15 overs, Saurashtra lost three wickets, including the dependable Ganesh Sathish (21) with Unadkat's pace bowling partner Hardik Rathod getting two of the three scalps and Unadkat the other one.
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Badrinath (17) and old warhorse Wasim Jaffer (41) then tried to do some damage control adding 33 runs before the Vidarbha skipper was bowled by medium pacer Chirag Jani.
Jaffer was clipping anything on his legs to the boundary and there were seven of them in his 41 before he was caught by Kamlesh Makvana off Deepak Punia.
Brief Scores: Vidarbha 1st Innings 151 in 50.4 overs (Wasim Jaffer 41, S Badrinath 17, Jaydev Unadkat 5/70)
Saurashtra 1st Innings 70/1 in 30 overs (Cheteshwar Pujara 45 batting).