Shirokov made the jump to the Russia's under-20 team in September 2004, posting the second-best record with Russia at the Four Nations Tournament. Several months later, he made his first of two appearance at the World Junior Championships. In 2005 he scored eight points in six games at the top under-20 tournament in Grand Forks, North Dakota, helping Russia to a silver medal finish, losing in the final to Canada. In April 2005, Russia hosted the Big Prize Tournament in St. Petersburg, where Shirokov recorded an assist in two games as Russia posted the best record.