Battle of Cape Matapan
"Stuart" and other ships of Waller's 10th Destroyer Flotilla supported the assaults on Tobruk in January 1941 and Benghazi the following month. In March, "Stuart" escorted Allied troop transports to Greece as part of Operation Lustre, narrowly avoiding falling victim to Axis dive-bomber attacks. During the Battle of Cape Matapan at the end of the month, Waller's ships were credited with sinking two Italian destroyers. From May to July, the 10th Destroyer Flotilla made 139 ferry runs during the siege of Tobruk, carrying supplies to the town's garrison and evacuating the wounded. Waller was mentioned in despatches twice during 1941: in July for his army cooperation role with the Inshore Squadron off the Libyan coast, and in November for his service during the Greek campaign. In January 1942, he was awarded a Bar to his DSO for "bravery and enterprise in the Battle of Cape Matapan".