Heimir Hallgrimsson's Republic of Ireland team are looking to cause a big shock against Portugal tonight in a bid to keep the World Cup qualifying campaign alive. Here's everything you need to know.

The Portugal squad is led by the evergreen Cristiano Ronaldo, who has the most caps of any player in history with 225. One boost for Ireland is that arguably the best left back in the world, Nuno Mendes, is missing through injury. Their squad is still full of quality with the likes of Bruno Fernandes, Vitinha and João Neves.