Starting on their overnight score of 10 for one in response to Rajasthan's 141 in the first innings, Delhi lost Varun Sood (8) early after play started post lunch due to dense fog in the capital, but the hosts soon gained ground to finish on 201 for three on a day when only 52 overs were possible.
Unmukt (87 batting) and Sehwag (64) made full use of the afternoon sunshine to stitch a 128-run third-wicket partnership and give the Gautam Gambhir-led side a vital 60-run first innings lead.
The duo helped Delhi accumulate 131 runs in the post-lunch session to take tea at 141 for two in 38 overs.
The tea-break though did not prove too good for Sehwag, 36, who got out to medium-pacer Shailender Gehlot's delivery.
It was a length delivery and Sehwag rightly played a pull-shot only to be holed out at mid-wicket.
Opener Unmukt, who struck his 10th first-class fifty, carried on with a firmer resolve from then on to stick around with veteran Mithun Manhas (34 batting) and manage an unbeaten 61-run partnership.
Sharing the new-ball with Deepak Chahar, Rajasthan's left-arm medium-pacer Aniket Choudhary, who had accounted for Gambhir for a duck on the opening day, has picked up two wickets so far.
Rajasthan stand-in-skipper Ashok Menaria tried to juggle with his bowling options on a tough day on the field but Delhi batsmen called the shots.
Brief Scores:
Rajasthan 1st innings 141 (Rajesh Bishnoi 57, Aristh Singhvi 28; Parvinder Awana 2-15)
