Nehra (6/16) picked up six wickets in his first six overs, leaving Vidarbha tottering at 33 for seven.
The ball was doing all sorts of things on a greenish deck, so much so that the match was stopped for around 30 minutes in the first session after Amol Jungade (28) was hit on the shoulder by speedster Parvinder Awana (1/26).
The game was resumed after the heavy and light rollers were used. Vidarbha's innings did not last too long after the unexpected break, ending in 31.1 overs.
In reply, Delhi were 96 for two in 48.3 overs with contributions from openers Unmukt Chand (37) and Gautam Gambhir (49).
In another Group A match in Hubli, double strike by paceman Manpreet Gony kept Punjab in the hunt as Karnataka slid to 59 for two after restricting the visitors to 174 in the first innings.
Karnataka, who won the toss and opted to field, struck telling blows as Punjab collapsed from 106 for one to 174 all out with opener Manan Vohra scoring a fighting 69.
Vohra and Uday Kaul (29) added 93 runs for the second wicket, but thereafter it was all downhill for Punjab whose skipper Mandeep Singh chipped in with 32.
In reply, Karnataka lost opener Mayank Agarwal (17) and No.3 Ganesh Satish (5) as Gony dismissed both as the hosts ended the day on 59 for two.
Mumbai 242 for 2 (Jaffer 125 not out) v Odisha
Punjab 174 (Vohra 69) v Karnataka 59 for 2
Haryana 266 for 2 (Sunny 139 not out) v Gujarat
Delhi 96 for 2 (Gambhir 49) v Vidarbha 88 (Nehra 6-16)
Madhya Pradesh 342 for 2 (Saxena 157 not out, Ojha 106 not out) v Saurashtra
UP 212 v Bengal 26 for 2 (RP 2-16)
Tamil Nadu 200 for 8 (Aparajith 29, Prasanna 88 not out) v Railways
Services 191 (Munaf 4-38) v Baroda 62 for 0
Hyderabad 234 for 3 (Akshat Reddy 99) v Goa
Maharashtra 106 for 1 v Kerala 151 (Samson 18)
Andhra 224 for 4 (Prashant 113 not out) v Himachal (Dhawan 0-33)
Assam 263 (Sharma 108) v Jammu and Kashmir
--IANS (Posted on 14-12-2013)