Manchester United clinched a place in the UEFA Youth League round of 16 on the back of two first-half goals and a professional performance in testing circumstances in Belgrade.
The Reds were without Luca Ercolani, Aidan Barlow and Tahith Chong, while Ethan Laird picked up a late knock despite being named on the bench. The hosts missed Lazar Kozic, who had been the star man in the earlier rounds but joined Dutch outfit Fortuna Sittard last month.
Angel Gomes was the next Red to be left in agony when caught by Milos Toseski and Uros Lukic showed the Serbian's threat with a couple of decent attempts that were not far away. However, Nicky Butt's men constructed by far the best move of the game to open the scoring.
Warren was heavily involved in the second goal on the half-hour mark as he picked up a corner by Gomes and managed to squeeze in a cross with his left foot. The centre came off Ivancevic's head and ended up in the back of Zravkovic's net.
Bohui was subjected to another poor challenge when Ognjen Mitrovic went in needlessly high on the forward and was fortunate to escape with a yellow card. Brodarac made life difficult with Matija Babovic failing to get any power in his header from Mitrovic's centre and Srdan Kocic's free-kick needing to be scrambled around the post by Reds keeper Alex Fojticek.
Babovic's curler sailed narrowly wide and, with it, the Serbian champions' hopes of getting anything out of the tie evaporated as United kept a clean sheet to advance to the last 16 of the competition.
MUTV is showing extended highlights of the game at 23:00 GMT on Wednesday night.