At stumps, Vidarbha were 20 for one with left-arm seamer Pradeep Sangwan cleaning up former India opener Shiv Sunder Das.
The day belong to young Rawal who scored his second first-class century of the season having scored his maiden ton against Tamil Nadu on debut.
The left-hander showed enormous patience batting close to six hours scoring 104. He faced 226 deliveries and hit 15 fours.
He had a very fruitful partnership with veteran Rajat Bhatia (68, 136 balls, 7x4, 1x6) as they added 152 runs for the sixth wicket having joined hands at 262 for five.
While Rawal dropped anchor at one end, Bhatia did hit a few big blows. Both Bhatia and Rawal were were out in quick succession but Delhi's lower-order batsmen showed a lot of grit.
Puneet Bisht (26), Sumit Narwal (39) and Pradeep Sangwan (37, 35 balls, 3x4, 2x6) added useful runs which took their total past 500. Narwal and Sangwan added 68 runs for the ninth wicket.
For Vidarbha, Sandeep Singh, Akshay Wakhare, Shrikant Wagh and Gaurav Upadhyaya took two wickets apiece.
With Odisha fighting it out for an outright win against UP, Delhi bowlers now have 180 overs to get the remaining 19 Vidarbha wickets which will help them get into the knock-out stage of the competition.
Brief Scores: Delhi 523/9 decl (Vaibhav Rawal 104, Unmukt Chand 82, Rajat Bhatia 68, Mithun Manhas 54).