Veteran Manhas (100) struck his 25th first-class century, while Sehwag hit some of his vintage shots during his 72-ball-56 as Delhi scored 448 for nine at stumps taking an overall lead of 360 runs at the end of the second day.
This was Sehwag's first first-class half-century of the season.
The pitch had bounce and lateral movement but it was the difference in class of the Delhi batsmen that was evident during the day.
The duo hit as many as eight sixes between them -- all were clean hits with Nehra scoring his first 50 in senior level cricket.
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All eyes were on the Roshnara track today after play was halted for 28 minutes yesterday with BCCI's chief curator Daljeet Singh also arriving to have a look at the proceedings.
But Sehwag and Manhas during their 101-run stand in 18 overs showed how to bat on a track that has grass and the bounce is a bit on the steeper side at times.
A Shrikant Wagh yorker was dug out effortlessly as the ball raced to the mid-wicket fence while a forward defensive punch through mid-on brought up his 50 off 62 balls with nine fours.