During the War of the First Coalition Quosdanovich first commanded a brigade, then a division. At the crucial defeat at Fleurus he commanded the second column. On 24 September 1795, while leading a division, he scored an impressive victory over two French divisions at the Battle of Handschuhsheim (now a district of Heidelberg). In July 1796 he transferred to Italy, where he led a corps under Dagobert Sigmund von Wurmser and József Alvinczi in four attempts to break the French Siege of Mantua. In the first, he lost the Battle of Lonato after a complicated series of maneuvers between 29 July and 4 August 1796. During the second relief, he participated in the Battle of Bassano on 8 September, but avoided being trapped in Mantua with Wurmser. In the third relief of Mantua he led the Friaul Corps in the Second Battle of Bassano and the Battle of Arcole. He led two brigades at the crucial Battle of Rivoli. He retired from the army in 1797 and died at Vienna on 13 August 1802.