 Anxious to revenge themselves against the Austro-Hungarians, the Regia Marina (Royal Italian Navy) made plans for a sneak attack on the two ships in their berths in the Bay of Muggia, near Trieste, by MAS launches. On the night of 9 / 10 December, two MAS boats managed to penetrate the harbor defenses undetected, and fired torpedoes at Wien and Budapest at 02: 32. The torpedoes fired at Budapest missed, but Wien was hit by two torpedoes fired by MAS 9, commanded by Lieutenant Commander (tenente di vascello) Luigi Rizzo, that blew a hole 10.5-meter (34 ft) wide abreast the boiler rooms. All of the watertight doors were open on board the Wien and the ship capsized in five minutes despite an attempt to counter her growing list by flooding the trim tanks on the opposite side. The attack killed 46 members of the crew. Both Italian boats escaped without being detected and Rizzo was awarded the Gold Medal of Military Valor.
