Given the hype accompanying the France-England encounter, there is a danger of ignoring the significance of the other Group B clash between Switzerland and Croatia.
A win for either team will put pressure on the more fancied teams, regardless of the result from Lisbon. Conversely, a defeat will confirm the suspicion that at least one these teams is vying for the minor places.
Switzerland coach Jakob Kuhn believes his players appreciate the importance of the opener.
“Croatia are a good side – most of their players play abroad,” said Kuhn.
“But we will go into that match believing we can get the win we need before facing England and France.
Swiss midfielder Raphael Wicky was another to stress the significance of today’s game.
“There would still be hope if we didn’t win,” said Wicky.
“However, it would make our task much harder because the other teams in the group are stronger than Croatia.
“If we allow them to play, then we will be in trouble because they are technically outstanding.
“In order to stop them getting into their stride, we need to put them under constant pressure.”
Meanwhile, Croatia coach, Otto Baric, has been pleased with his team’s preparations.
“We have been working very seriously and we have had maximum concentration on our preparations for the first game,” he said.
“We have had a few problems with two or three players – Boris Zivkovic, Ivica Olic and Milan Rapaic – but thanks to the medical staff, the doctors and the physiotherapists, they are getting better every day.
“I would say they are 99% fit and ready and they will play.
“It’s true that this is a big game for both teams, but all three matches are important.
“Every game is equally important for each team and each match is as special as the first, but of course it is important to get off to a good start.”
Croatia suffered a major blow when Croatia keeper Stipe Pletikosa tore a thigh muscle in training, meaning he will miss the game. Tomislav Butina is expected to take his place in goal.
“Butina is an excellent goalkeeper,” he said ahead of Sunday’s game against Switzerland,” said Baric.
“Before he left for Brugge two years ago, he was the goalkeeper for Dinamo Zagreb for many years.
“He really is a very, very experienced goalkeeper and I have my full, 100 trust in him.”
Milan Rapaic is set to come in for Ivica Olic and experienced defender Igor Tudor is suspended.
Switzerland coach Jakob Kuhn is hopeful midfielder Johann Vogel will recover from a thigh injury. Vogel has been undergoing intensive treatment since arriving in Portugal and is expected to play.
Croatia: Butina, Simic, Simunic, Bjelica, R Kovac, Zivkovic, Rapaic, Mornar, Prso, N Kovac, Sokota.
Switzerland: Zuberbuhler, Haas, M Yakin, Henchoz, Zwyssig, Spycher, Magnin, Vogel, Gygax, Celestini, Wicky, Huggel, H Yakin, Chapuisat, Frei, Vonlanthen.
Referee: Lucillo Batista (Portugal)