Greece was not invaded either by allied armies but in truth both countries benefited from a retreating German army that pulled out more than being thrown out.
Not to be too much of a nitpicker, but Hitler ordered the withdrawal of troops from Greece and Yugoslavia on Aug 26, 1944. Germany had its hands full by that time, and US troops had landed in Italy, Normandy, and Toulouse several months earlier, and liberated Paris the day before.
Greece benefitted immensly from Allied troops and supplies. British troops liberated Athens on Oct 14, 1944.
Yugoslav army and partisan fighters received materiel from the Allies (Russia and USA), and ground troops from Russia assisted the Yugoslavs throughout the war and participated in the liberation of Belgrade and Dubrovnik.