Thibaut Courtois believes "now it's all or nothing" for Belgium in the World Cup after their goalless draw against Iran on Sunday.

Despite accumulating 1.79 expected goals (xG) from 23 shots and having 70.1% of possession, Belgium, who saw Nathan Ngoy sent off, were unable to get the better of a spirited Iran side.

Belgium's 23 shots are their most without scoring in a World Cup game since 1994 against Saudi Arabia (28).

Indeed, their players have fired in 69 shots at the finals since a Belgium player last got on the scoresheet (Michy Batshuayi v Canada in 2022).

Rudi Garcia's side are third in Group G, though they can still guarantee themselves a top-two finish if they beat New Zealand in their final game on June 26.

Courtois insisted Belgium must defeat New Zealand, but cannot afford to underestimate the All Whites.

"Iran played in a block, even lower and more closed than we had expected. They played in a sort of 5-4-1. That made it difficult," said the Real Madrid goalkeeper.

"We absolutely have to win against New Zealand. Although I expect a similar match with eleven men in the box.

"If we score, the game will open up. [Against Iran] we lacked some precision on the counter-attack.

"Now it's all or nothing. We're better than New Zealand, but it's always more difficult in a World Cup.

"Just look at the 0-0 draw between Spain and Cape Verde or the 0-0 draw between Ecuador and Curacao."

Iran are second in Group G ahead of their final game against Egypt, with Ardeshir Ghalenoei's side still within a chance of topping the group.

The head coach was delighted with how his side have performed at the tournament so far, especially considering their obstacles off the pitch.

"We came into the World Cup under the worst possible conditions," Ghalenoei told reporters.

"And still we got a result against a great team and a great manager. We played a beautiful game.

"We had two great games without losing. Tonight [after Belgium draw], we celebrate. Tomorrow, we focus on Egypt, which is a very strong team."