Deco's superb 25-yard strike and Cristiano Ronaldo's penalty gave Portugal a 2-0 World Cup Group D win over Iran and a place in the knockout stages in Germany.

Luiz Felipe Scolari's troops made hard work of wearing down Iran's defence in Frankfurt - but their resolve was finally broken on 63 minutes when Deco lashed home a first-time curling strike, and Ronaldo coolly converted on 80.

Portugal started the game in a laboured manner but Deco drew a fantastic one-handed save from Ebrahim Mirzapour, who turned the Barcelona playmaker's close-range half-volley over the crossbar.

Ronaldo had a header cleared off the line before steering a fierce drive into the sidenetting - and for Iran Andranik Teymourian's 30th-minute shot hit the upright but he was flagged offside anyway.

Miguel had the last chance of the first half but Mirzapour's save deflected his low shot narrowly wide of the upright.

The opening goal did not come until just after the hour, when Luis Figo rolled the ball into Deco's path and watched him unleash an unstoppable piledriver into the back of the net.

Rasoul Khatabi scuffed an angled shot just wide for Iran on 69 minutes and Vahid Hashemian's header was well saved by Ricardo on 78.

But Figo was scythed down by Yahya Golmohommadi in the 18-yard box two minutes later, and Ronaldo made no mistake with the spot-kick.

The victory puts Portugal top of Group D with six points from two games.

And a draw in their final game against Mexico on Wednesday would see them go through as group winners.