Richard Dunne believes victory over Bulgaria on Saturday will have Republic of Ireland well on course for the 2010 World Cup.
The Irish face the Bulgarians at Croke Park on Saturday, before tackling Italy in Bari four days later.
The reigning World Champions are favourites to top Group Eight, with the rest left to battle it out for a runners-up spot.
Dunne accepts that will more than likely prove to be the case, making a weekend clash with Bulgaria all the more important.
Ireland and Italy are currently locked together at the summit, having taken 10 points from four games, while Bulgaria's challenge could be killed off in Dublin if they fail to build on the three points they have taken from their opening three fixtures.
"This is the bigger game, really," said the Manchester City defender.
"This is the one we have to win because when the group was drawn, I suppose everyone thought 'Italy are through and the rest can fight it out'.
"We have to make sure Bulgaria are 10 points behind us come Sunday morning, and then we will go into the Italian game full of confidence.
"We believe within our own group that we can upset the Italians and we can take points from them as well."
Dunne believes Ireland are perfectly placed to reach their first major finals since the 2002 World Cup and is backing Giovanni Trapattoni's men to be among those competing for international glory in South Africa next summer.
"We have had big ones when we did actually qualify, but in recent times, this is as good an opportunity as we have and in that sense, the two games are massive.
"And this first one probably more so because if we can beat Bulgaria, it will hopefully get them out of the way and we can fight it out for top spot with Italy.
"The manager has been picking the strongest squad he possibly can and once we are all fit and everyone is free from suspension, we have got as good a chance as we have had for a long time."