The highlight of his international career was undoubtedly winning the UEFA European Championship for Greece at Euro 2004. He was a key player for Greece and famously scored the first goal of the tournament against Portugal, a stunning long-range shot that shocked the hosts and gave Greece the confidence they needed to win the game and progress in the tournament. After winning Euro 2004, Karagounis continued to play on a regular basis for Greece in the 2005 FIFA Confederations Cup, the 2006 World Cup qualifying campaign and the Euro 2008 finals. On 26 March 2008, Karagounis participated in a Greece–Portugal friendly match in Düsseldorf. This proved to be somewhat of a highlight of his international career, as he scored two almost identical well-placed free-kicks to give Greece a 2–1 victory.