Medium-pacer Alok Mangaraj scalped wickets to help Orissa dismiss host Tripura for 108 in the first innings on the opening day of their four-day East Zone under-22 C K Nayudu Trophy match at Agartala today. But the bowling success was neutralised considerably as Orissa suffered similar batting failure to be reduced to 75 for five at close. Brief scores: Tripura 108/10 in 36.2 overs (MS Murasingh 29: Alok Mangaraj 6/36, Dhiraj Singh 3/3) vs Orissa 75/5 in 38.5 overs (Natraj Behera 30, Tukuna Sahu 21: R Sharma 4/17).