Long's goal defeated Germany in October in qualifying for Euro 2016 and he went on to enjoy a superb season with Southampton, in which he scored 10 goals in 28 Premier League appearances.
Now, Long has his sights set on Zlatan Ibrahimovic's Sweden.
"For four months now I've been waiting for this Sweden game and I just really want to get out there and get the result we deserve," he said. "We've worked hard to get here, we've come from a difficult situation in the group to qualify.
"And it would be a shame to just throw it all away in the first game.
"So that's our full motivation – to go out there and beat Sweden and put ourselves in a good position to qualify.
"We're fully focused on that Sweden game and we'll try to not let the occasion get to us."
Long said his side loved proving people wrong, pointing to their road to qualification.
"After we drew to Scotland, everyone was saying it was a three-horse race and Ireland were out of it," he said.
"It really spurred us to go on. Of course we relied on a few other results to go our way but we still had to capitalise on our games.
"Just to qualify is an amazing feeling. We've been here once before and we didn't really perform the way we should have or the way we can. And we've been regretting it for four years. So hopefully we can put that right this time."