After the death of Ali Pasha Omer was among the commanders who were sent by Hurşid Ahmed Pasha, the new commander-in-chief, to suppress the Greek Revolution which had broken out in March 1821. On 24 April 1821, he defeated the Greeks at the Battle of Alamana and had their commander, Athanasios Diakos, impaled. Vrioni's advance was temporarily halted by Odysseas Androutsos who, with a handful of men, inflicted heavy casualties upon him at the Battle of the inn of Gravia on 8 May 1821.