In September 1796, Weyrother transferred to Northern Italy, where he fought in the Battle of Bassano under Field Marshal Dagobert von Wurmser, distinguishing himself at the Battle of Bassano on 6 November 1796. He then joined the renewed effort to relieve the Mantua, serving on the staff of Feldzeugmeister József Alvinczi, helping to plan the campaign, which ended in a narrow defeat by Bonaparte at the Battle of Arcole. His own plan for the Battle of Rivoli provided for three widely separated striking forces and unrealistically called for one flanking column to march across mountainous terrain in January. His plans were compromised by Napoleon's chief spy, Toli, who obtained a copy of the plan for the advance in January 1797, which ended in a decisive Austrian defeat at the Battle of Rivoli and the consequent surrender of the fortress of Mantua.