At stumps, Rest of India were 102 for 2, seven runs ahead of Vidarbha, with Ajinkya Rahane and Hanuma Vihari in the middle.
Resuming proceedings at 245/6, Vidarbha ended their innings with a 95-run lead as the lower-order once again led the fightback.
Karnewar and Akshay Wadkar stitched together a 79-run partnership which helped Vidarbha take a crucial first innings lead. Rahul Chahar then removed Wadkar for 73 as he dragged one onto his stumps.
However, Karnewar upped the ante and added 76 runs along with Akshay Wakhare - who contributed just 20. Karnewar departed soon after completing his ton (102) as Chahar once again got the important breakthrough.
The teenage leg-spinner was the pick of the bowlers, ending with figures of 4/112 as he showed great control on his line and length. However, lack of support from the other end allowed the Vidarbha batsmen to add to the scoreboard.
Rest of India's misery didn't end anytime soon as Rajneesh Gurbani (28) and Yash Thakur (10) added 39 runs for the final wicket to help their side cross 400. Ankit Rajpoot finally dismissed Thakur as Vidarbha's innings ended at 425.
The openers needed to start well for the visitors but that didn't materialise as Anmolpreet Singh's attacking instincts got the better off him. The left-hander played into Sarwate's trap as he mistimed one straight into long on's hands while trying to clear the boundary.
Hanuma Vihari and Mayank Agarwal were looking solid but Vidarbha kept up the pressure by not giving away any easy runs or boundaries. That paid immediate dividends, as Agarwal lost his patience and looked to hit against the turn but failed to connect, finding long off. He departed for 27.
Skipper Ajinkya Rahane joined Vihari in the middle and the two tackled Vidarbha's spinners with great ease. They put together an unbeaten 56-run stand which helped Rest of India take a seven run lead by the close of play.
The two will like to bat on tomorrow and ensure they set Vidarbha a sizeable target. However, Vidarbha will also back themselves to tear through Rest of India's batting with the pitch constantly deteriorating and assisting the spinners.
Brief Scores - Rest of India 330 and 102/2 (Vihari 40*, Wakhare 1/31) lead by 7 runs against Vidarbha 425 (Karnewar 102, Wadkar 73, Chahar 4/112)
Aditya SarwateAkshay KarnewarAkshay Wakhareanmolpreet singhHanuma Vihari Ajinkya RahaneIrani Cup 2019mayank agarwalRajneesh Gurbanividarbha
First Published: February 14, 2019, 4:57 PM IST