Keith Andrews insists Republic of Ireland can still qualify despite their opening Group C loss to Croatia on Sunday.
Following a 3-1 defeat by Slaven Bilic's men in Poznan, Ireland head into their showdown with the reigning world and European champions knowing defeat would end their Euro 2012 campaign with a game still to play.
Indeed, even a draw could end their hopes if the result of the Croatia v Italy match goes against them.
But Andrews will not give up hope that Giovanni Trapattoni's men can get the points they need to secure a prolonged stay in Poland and Ukraine.
He said: "We have to believe we can or else we might as well go back to Dublin now.
"It was always going to be a difficult group and it certainly proved that last night. The way we have started, we have given ourselves an uphill task."
The game in Gdansk will prove a particular test for Andrews and his midfield colleagues as they attempt to contain and overhaul the likes of Andres Iniesta and Xavi, although he is adamant the challenge holds no fears.
Asked if the prospects would give him sleepless nights, the 31-year-old said: "No, I don't think so. We are obviously against top teams - the three teams are fantastic sides.
"Croatia showed that at times last night and Spain will be probably an even sterner test.
"But I think we can play better than we did last night as well and hopefully we can do that on Thursday."
Ireland fell behind after just three minutes against Croatia when striker Mario Mandzukic headed past Shay Given.
Although defender Sean St Ledger levelled with a 19th-minute header, the respite was short-lived as Everton striker Nikica Jelavic restored Croatia's lead two minutes before the break and Mandzukic made it 3-1 within three minutes of the restart.
Andrews said: "It was very difficult. Basically, we conceded goals at the wrong times.
"There's never going to be a good time to concede goals, but certainly in the first three minutes and then just before and just after half-time are probably cardinal sins in football.
"You are taught that at schoolboy level. We shot ourselves in the foot.
"We were under no illusions - they are a fantastic side. It wasn't a case of us being over-confident.
"Our preparation was spot-on, our build-up, we were going in full of confidence, but with the utmost respect for the team.
"We felt we could achieve a result and unfortunately, we weren't able to do that."