After fencing with the Viceroy near Soave and Monte Bastia at the Battle of Caldiero at the end of April, the archduke withdrew on 2 May. The retreat was ably covered by Feldmarschall-Leutnant Johann Maria Philipp Frimont's rear guard. On 8 May, John defended a strong position behind the Piave River. In the Battle of Piave River, Eugène defeated his opponent, inflicting 5,000 casualties while suffering about 2,000 killed and wounded. On 11 May, the Franco-Italian advance guard turned both flanks of Frimont's 4,000-man rear guard at San Daniele del Friuli. The Austrians were crushed with losses of about 2,000, while French casualties numbered between 200 and 800. After a clash at Venzone, Frimont retreated north up the Fella River valley, burning the bridges behind him.