Put into bat on a seamer-friendly Roshanara track, Sehwag (3), Gambhir (29), Unmukt Chand (1) and Mithun Manhas (9) were all back in the pavilion before lunch to trigger a collapse from which Delhi couldn't fully recover.
Although Rajat Bhatia (39) and Vaibhav Rawal (25) added 59 runs for the fifth wicket, Haryana's five-man seam attack maintained the pressure throughout the day by not giving away easy runs.
Punit Bisht scored a quickfire 33 with six fours and a six but didn't last long.
All eyes were on Sehwag and Gambhir but both of them looked horribly out of touch as Joginder troubled them on a track that had good carry as well as movement after pitching.
After Unmukt was dismissed trying to hit a cover drive off Badhwar, Sehwag walked out there in the middle in the very second over.