One of the stingiest teams at Russia, Iran's departure from the World Cup will be a relief to teams that might have faced them in the knockout rounds.

The Asian powerhouse bowed out with a typically attritional 1-1 draw against Portugal on Monday, their fans heartbroken after Mehdi Taremi missed a last-gasp effort that would have fired them into the knockout rounds for the first time.

Their Portuguese coach Carlos Queiroz, a self-described "bad loser", was incensed by the result, teeing off at the refereeing and renewing his attack on the VAR system that he said had let Cristiano Ronaldo off the hook for an elbow to the face.

Once the dust clears, Queiroz and Iran should feel hugely proud of their achievements, which included a first World Cup win in 20 years and all but grinding through one of the tournament's toughest groups.

Few gave them much chance of reaching the Round of 16 in a pool also featuring Spain and Morocco, and their preparations were disrupted by political problems, with Nike declining to supply boots over concerns it would breach US sanctions.

Iran's ability to nullify the attacking threat of the Iberian powers may be closely examined by the teams that remain in the tournament.

Morocco could find no way through the Persian stonewall in a 1-0 loss and neither could Spain until they conceded a fortuitous Diego Costa goal, the result of a deflection pinging off his knee from an attempted clearance.

It took a wonder goal by Ricardo Quaresma to put Portugal on the scoresheet.

Iran's goalkeeper Alireza Beiranvand, who slept rough on the streets of Tehran as a junior while pursuing his football dream, could do nothing to stop either of the goals.

But he departs with reputation enhanced, his brilliant save on Ronaldo's spot-kick a crowning moment in a fine tournament.

Iran's problems were down the other end, though, where team spirit and the dogged application will only get you so far.

Far from playing a negative game, they created enough chances to score a hatful of goals but were let down repeatedly by a mix of bad luck and poor finishing.

It took an own goal from Morocco to secure victory in their opener and a penalty to grab the equaliser against Portugal.

Alireza Jahanbakhsh's dominant form in the Dutch top flight was nowhere to be seen, and talented young striker Sardar Azmoun was also ineffective.

Iran leaves Russia with acclaim but also uncertainty over their future as Queiroz departs after seven years in charge.

A master tactician, one of his greatest coups was to forge a unity of purpose among players from diverse backgrounds and build a team strong enough to withstand the political and economic challenges of playing football in Iran.

His replacement may find it a hard act to follow.