Martin O'Neill warns Denmark not to underestimate Ireland

The two men played together at both Manchester City and Norwich during the 1980s and the Norwegian, now in charge of the Denmark national team, at one point rented the Irishman's home.

However, they will be in opposing dug-outs at the Parken Stadium in Copenhagen on Saturday evening with Ireland once again attempting to upset the odds to head for Russia at the expense of the seeded Danes.

O'Neill said: "Generally, we have been up against it most of the time in the last couple of years. The Euros group was a pretty difficult one and we managed to come through that through the play-offs.

"This was even more difficult because only the top side would go through automatically. We were fourth seed, but we have managed to make it so far and we have had some big battles.

"We had to win in Wales, we had to win the last two games to manage that and we take our position here on merit, that's the point, so we have got to go again.

"I don't think for one minute, in all seriousness, the players think that this game is anything but difficult. Of course it is, really difficult.

"Denmark have got some excellent players who can cause a lot of problems - [Christian] Eriksen has been playing fantastic football now for maybe 16 months, but he's not the only Danish player who can play.

"They have got some really good players - but so have we. We are going to try to play to our strengths - we are going to try to play strongly, we're going to have to be able to defend properly when it comes to it and we are going to have to take our chances.

"That's what we are going to have to do and over the two legs, we will give ourselves a chance, we hope."

If that means ending his old friend's dreams, O'Neill will have no qualms about doing so, although he retains huge affection for former defender Hareide.

He said with a smile: "Since I was a better player, I was earning more money than he was and Age had no place to stay originally, so he stayed with me.

"I charged him very, very cheap rent and he turned out to be a really good player, so I'm going to send him the bill.

"He has an excellent reputation as a coach and he did really fine as a player."

There is another familiar face in the Denmark camp for O'Neill, who expects to have full-back Stephen Ward and midfielder Jeff Hendrick fit for the first leg, in the shape of striker Nicklas Bendtner, who played under him briefly at Sunderland.

Asked about the frontman, the 65-year-old said: "Nicklas? Very interesting, as only Nicklas can be.

"When he set his mind to it, he was excellent."