The striker headed in the only goal of the 1-0 win over Bulgaria on Friday as Cesare Prandelli's side moved seven points clear at the top of Group B with three games to go.
The 31-year-old credited the team for navigating what he considered to be a tricky tie and he hopes to be celebrating reaching the Brazil finals following their clash with Czech Republic on Tuesday.
"I'm happy to have got the breakthrough because it has been a very complicated match," he told reporters. "Their defence was extremely tight and it has been difficult for us to find spaces.
"Therefore I'm very happy to have managed to unlock the match thanks to my goal.
"On Tuesday we'll be playing against the Czech Republic in Turin and we want to close this phase in the best possible way. We want to make a good performance in order to win and celebrate the qualification."
Italy defender Giorgio Chiellini echoed his team-mate's comments and admitted he was proud of their performance against Bulgaria.
"We usually suffer during the first match in September," he said. "It has always been so in the past. We had a good performance in the second part of the first half of the match by holding the ball's possession and trying to find spaces.
"In the second half of the match we have been a bit too static, probably due to our physical condition.
"In any case we're happy for the result which brings us closer to the qualification. We hope we'll be able to celebrate the qualification already in Turin next Tuesday."
Ignazio Abate and Luca Antonelli - who both picked up injuries against Bulgaria - have been replaced in the Azzurri squad with Fiorentina's Manuel Pasqual and Sampdoria's Lorenzo De Silvestri, while Lorenzo Insigne is expected to withdraw after picking up a knock.