No dilution of standards
I think it's marvellous that a nation the size of Iceland is taking part and I fully agree with the decision to expand the tournament to 24 teams.
It has given an incentive for middle-ranking European countries to push really hard for qualification, knowing they now have a realistic chance.
The likes of Albania and Iceland are encouraged to become more professional, to concentrate on improving their coaching.
I played against Iceland many times with Ireland and they are now a far tougher proposition for opponents.
The expanded format does not appear to have diluted standards. After the first round of matches no team has been rolled over.
The sides that have won by more than a single goal - Hungary, Germany and Italy - only did so via late second goals.
Defence handled Ronaldo well
Centre-back is one of Iceland's weaker areas, but in general they coped reasonably well with Cristiano Ronaldo, who filled a more central attacking role than he normally does for Real Madrid.
Man-marking can be an effective way of countering skilful players such as Ronaldo, but I don't think Iceland have anyone capable of such a task.
Ronaldo has certainly recovered the fitness he was missing badly when he faced Manchester City and Atletico Madrid in the final two hurdles of the Champions League this season.
The holiday he took after Real had won the competition, while Portugal were playing a pre-tournament friendly against England, has benefited him.
He was not quite at his best but he is definitely getting there.
Knockout phase beckons
Iceland must stand a good chance of advancing to the knockout phase in what is their first leading tournament.
They must remember that Portugal are by far their strongest opponents in Group F, so to get a draw was a remarkable achievement.
Portugal are really strong defensively, they have top-class midfielders such as Joao Moutinho and Renato Sanches, and then of course there is Ronaldo in attack, not forgetting Nani, who remains a fine talent.
I definitely think Iceland can get something from the games against Austria and Hungary, the other teams in this section.
Neither of those sides were particularly impressive when they faced each other.
Correct use of tactics
I've always said that 4-4-2 is the best formation to deploy with a lesser calibre of players at your disposal, and Iceland have done exactly that.
It is the easiest way to play. Everyone knows their job and what positions to take up whether they or the opposition have the ball. If you ally that with hard work, as Iceland do, then you become formidable opponents to break down.
Iceland's set-up helped them get through their qualifying group, finishing above the Netherlands and Turkey.
They have not pressed as high as Leicester City did last season but otherwise they are similar, keeping things simple and very well drilled.
They sit back a little and are waiting for you when you get into certain areas.
Sigurdsson shows his quality
Iceland don't have the luxury of having plenty of top players in their squad: Gylfi Sigurdsson is probably the closest they have to a star.
He usually plays just behind the striker for Swansea City, or even in a false nine position, but I think Iceland decided they probably had enough up front, so they moved Sigurdsson to help out in central midfield.
He has a good scoring record, is excellent at free kicks, and has been a Premier League regular for many years.
THE TIMES, LONDON