Ireland only just missed out on a place at this summer's FIFA World Cup™ finals as a cruel combination of factors denied them a trip to South Africa.
However, the confidence they have gained in a little more than two years under veteran Italian manager Giovanni Trapattoni saw them draw home and away with reigning champions Italy in their qualifying group and then only just lose out to France in the play-offs due to a hotly-disputed goal.
Instead of heading off to the summer jamboree, Ireland will continue their preparations for the UEFA EURO 2012 qualifiers, which start in September, against Algeria at the RDS tomorrow night and Keane insists they have already proved they need not doubt their own ability.
He said: "If you look at the teams we have been playing against - France, Italy, Bulgaria - you couldn't watch any of those games and say they were better than we were. Mentally as a nation, we need to get that we are as good as everyone else.
"Everyone sees Ireland and says, 'they are not as good as France and Italy', but we have proved that we are, and if the players go into games believing we are as good as any team we play against, we have got a chance."
Trapattoni's critics accused him of adopting a negative approach in the FIFA World Cup qualifiers, and while their points return was more than creditable, every game in which they were involved was tight, sometimes agonisingly so.
However, while Keane admits a few comfortable victories would be nice, they are unlikely to be handed many of those on a plate.
He said: "You don't want to be scraping through games and biting your fingernails in the last few minutes, but you are playing against good teams and good players have the ability to do something special, so you have to be aware. We will look forward to a good game tomorrow and hopefully we can finish with a good win and look forward now to the next campaign."
Despite the heartbreaking failure to make it to South Africa, Trapattoni has pronounced himself satisfied with his first two years at the helm and brushed aside speculation that he could be the man to replace Jose Mourinho at Inter Milan.
He said: "I am satisfied with this team. We still have room to improve and grow with this team. We are a good team. I see many international games, but our discipline, our mentality, our attitude is very, very important, and we also have players with quality.
"We have played Italy, France, Brazil, Paraguay and now Algeria in the last six months and we can think we also have a strong team. We cannot be arrogant, but we have to be aware we are a strong team as well."
Trapattoni will hand a senior debut to 19-year-old Manchester City full-back Greg Cunningham, while Derby midfielder Paul Green, who appeared as a substitute in the 2-1 win over Paraguay on Tuesday evening, will make his first start. Both men impressed during last week's training camp in Malahide and were retained when the senior players joined up on Sunday.
Trapattoni said of Cunningham: "He is not afraid on the ball and he has personality. He can pass the ball immediately as well as hold on to it when he needs to, and that is very, very important."
The game will bring an end to Ireland's international season, and Trapattoni will watch the World Cup from afar. But asked how his compatriot Fabio Capello and his England team might fare, he said: "England, Germany, Spain, Argentina and Brazil, they will be teams who have the possibility to make the semi-finals. But who, before Euro 2004, talked about Greece winning? That's football."