Iran coach Branko Ivankovic believes his team can still progress to the knockout phase despite kicking off their World Cup campaign with a 3-1 defeat against Mexico.

The Persians are rooted at the bottom of Group C following the loss at Nuremberg's Franken Stadion as two goals in three second-half minutes gave the Mexicans a victory they deserved on the strength of their display in the final period.

That means Ivankovic's side go into Saturday's meeting with Portugal needing to win to have any serious chance of making it through to the last 16 for the first time in their history.

"We are thinking about the second game against Portugal and we will try to do something," said the Croatian. "Everything is not over just because of today. This is football and anything is possible. Portugal is a team like Mexico and we will try to do our best."

Ivankovic's side dominated the opening 45 minutes against the Mexicans and at half-time appeared set for a famous result that would have put the Iranians in position to challenge for one of the group's two places in the second round.

But a tactical switch by opposite number Ricardo La Volpe went unanswered by Ivankovic and goals from Omar Bravo - who also gave Mexico the lead in the first half - and Brazilian-born midfielder Zinha steered the Mexicans past a visibly tiring opponent.

Ivankovic put the disparity in his team's displays in the first and second half down to a lack of preparation by his key players, in particular Bayern Munich's Ali Karimi, Vahid Hasehmian of Hanover 96 and SV Hamburg midfielder Mehdi Mahdavikia.

"We have had a lot of problems in our preparations over the last few months," he said.

"This was Karimi's second game in the last three months, Hashemian was also injured for two months and Mahdavikia could not practice for the last 10 days. Also we were without (Fereydoon) Zandi because he is injured."

However, Iran's capitulation was kick-started by a dreadful error in defence by goalkeeper Ebrahim Mirzapour, whose poor clearance put his back line under pressure and another mistake by Rahman Rezaei gifted possession to Zinha, who set up Bravo for the all-important second Mexican goal.

"We didn't make so many mistakes, just one and it was a serious mistake," said Ivankovic. "But now we have six days before the game against Portugal and we will see how things are over the next two days.

"In the first half we played very well but it was because of individual mistakes and nobody can take care of individual mistakes. That's always the case for my team and everybody's team. Nobody can take care of this because this happens in the game."

Prior to the game the Iranians replaced injured defender Sattar Zare in their squad with Moharram Navadkia after Zare was ruled out for the duration of the tournament with a knee-ligament injury sustained during training last week.

(reopens) Meanwhile, Mexican Football Federation president Alberto de la Torre insists his side's victory has not changed their game plan for the World Cup.

"For me, the expectations are the same," he said.

"We must go on playing match-by-match and take this result as what it really is - we won one game and must wait for the next one and play all of them as a final.

"We've heard the national anthem in a stadium filled with green shirts and we loved it, but we have to keep on dreaming."

Zinha believes the team need to be more physical on Friday, when they take on Angola.

"We have to take the initiative and be more aggressive," said the diminutive midfielder.

Of his World Cup debut, which saw him replace Guillermo Franco at half-time, Zinha added: "It's something indescribable and I'll remember it for the rest of my life."

Head coach Ricardo Lavolpe played down injury concerns over record scorer Jared Borgetti, who was forced out of the game five minutes after half-time with a hamstring problem.