Glenn Whelan believes next month's World Cup qualifying meetings with Sweden and Austria will be among the most important games he has played in a green shirt.
The Stoke midfielder won his 50th cap for the Republic in their goalless draw with Wales in Cardiff on Wednesday night.
The 29-year-old could have marked the occasion with a goal, but dragged well wide after being teed up smartly by Robbie Brady.
Having enjoyed his landmark appearance for the Republic, Whelan quickly turned his attention to next month's double-header, which will go a long way to deciding whether Giovanni Trapattoni's side get to contest a play-off for a spot in the finals.
Whelan helped Ireland successfully qualify for Euro 2012, but with Sweden and Austria locked with them on 11 points, the games in Dublin and Vienna are as important as any he has been a part of.
"It was great to get my 50th cap," he said. "It was not something I ever expected and it was good for us to get a result, even though we had the chances to win it.
"Now we have two massive games next month, it is the most crucial double-header we have had during my time in the team.
"We can still do it, but we can only focus on that first game against Sweden and getting the win we need.
"Everyone will know after those games if we have a big chance of going to Brazil or not."
One of the bright points of Ireland's performance in Cardiff was the display of Hull midfielder Brady.
The 21-year-old Manchester United product was a lively presence, showcasing some nice footwork and incisive passing.
And Sunderland defender John O'Shea, who saw Brady come through the ranks at Old Trafford, believes he can go from strength to strength.
"He has the exuberance of a real confident player and it is really showing in his football," he said.
"You can see the ability he has got. He was only getting rare glimpses at United, but he is getting it regularly now.
"He has a real taste for it and I am sure he will be good for us and for Hull City."