Portugal started to seize control as the half wore on, though, and Vieirinha gave Hannes Þór Halldórsson some problems with a shot from distance on 18 minutes.
Ronaldo, who made his 127th appearance for Portugal, equalling Luís Figo as his nation's most capped player of all time,[5] then missed a headed chance before just failing to make an impact from a cross, which was delivered by Pepe.
Portugal looked to reassert their possession but were struggling to make things happen, as when Ronaldo produced a skillful flick to spark a move on 56 minutes but was ultimately crowded out as he tried to engineer space for a shot.
Moreover, Ronaldo also fired just over as Portugal broke away on the counter, with Iceland continuing to pursue an ill-advised handball appeal at the other end.
On 85 minutes, as Portugal were increasing the pressure, Ronaldo was presented with a cross at the back post by Nani; but his header was gathered by Halldórsson at the second attempt.