Roy Keane insists the Republic of Ireland will head into Sunday's Euro 2016 showdown with surprise Group D leaders Poland with nothing but victory in mind.

The Poles currently sit on top of the pile, three points clear of Germany, Scotland and Ireland having claimed the scalp of the newly-crowned world champions in Warsaw in October.

Martin O'Neill's men, the Germans and the Scots are locked together behind them on seven points, but assistant manager Keane is adamant there will be only one approach as the Republic attempt to close the gap at the Aviva Stadium.

He said: "A win would be nice after the disappointment of [November's 1-0 defeat in] Scotland.

"You can't have too many draws. Some days, you get good draws and bad draws, like the one in Germany is no doubt a good one. But the mindset at home is to go win the match.

"Afterwards, a draw might not be a bad result, but our mindset before the game is to go and get the win. The slip-up in Scotland is one that we don't want to cost us too much, but the mindset with the manager, staff, players and fans behind us has to be to go try win the football match."

The Aviva Stadium will be packed to the rafters on Sunday as Ireland set about their task of hoping to rekindle the memories of their last major victory on home soil, the famous 1-0 win over Holland in which Jason McAteer's goal set the nation on the road to the 2002 World Cup finals.

Keane played in that game and set the tone for the afternoon when he thundered into a first-minute tackle on Marc Overmars.

Asked if he could wield the same sort of influence from the sidelines this time around, he replied: "No, I cant tackle anyone can I?

"No, it's difficult, but we have good players and good characters. Creating a good tempo in the game can come from anyone. Some days it's a tackle and others, please God, it's goals."

Lansdowne in its current incarnation has perhaps proved less of a fortress than in its past, and Keane admits the Republic have to make life more difficult for visiting teams.

He said: "It used to scare the home team! If you want to do well in any campaign, you have to have a decent home record.

"I'm guessing a lot of teams have come here and enjoyed the Aviva, but it's up to us to be on the front foot and get the fans behind us. The atmosphere will be brilliant, but it cant just come from the fans, it has to come from the players too.

"But we will be making tackles, creating chances and putting bodies on the line, and that will get fans right behind us.

"The old Lansdowne was brilliant, always a great atmosphere. But in terms of the atmosphere for Sunday? That's the least of our worries. That will take care itself, I think it will be electric."

Keane met up with O'Neill, the rest of the staff and the players on Sunday for the first time since relinquishing his similar role at Aston Villa under former boss Paul Lambert, and he remains convinced he made the right decision.

He said: "I hope so, that was the aim when I left Villa, to focus on Ireland a bit more. It was a chance to get to games and see the players a bit more often, so that's not an issue.

"I was always comfortable with the decision and I felt it was right for everybody."

Keane spoke to the media after a training session in which James McClean, Stephen Ward and Darron Gibson were unable to take part because of injury, and within hours, Everton midfielder Gibson's persistent groin problem forced his withdrawal.

A statement said: "The Football Association of Ireland today confirmed that Darron Gibson has withdrawn from the Republic of Ireland squad to face Poland on March 29 due a persistent groin injury.

"Darron will return to his club today for treatment."

Full-back Ward's ankle remains a concern, but winger McClean said he is "100 per cent" sure he will be fit after a scan on his left ankle on Tuesday revealed no lasting damage.