Leo Beenhakker's Poland side looked to be heading for a comfortable victory when substitute Roger Guerreiro added a 47th-minute second goal to skipper Mariusz Lewandowski's early opener.
But having earlier seen midfielder Damien Duff pass up three glorious opportunities, Ireland belatedly discovered their touch in front of goal to set up a tense finish.
Substitute Stephen Hunt reduced the deficit with an 88th-minute penalty, and after Robert Lewandowski had restored his side's two-goal advantage, fellow newcomer Keith Andrews marked his senior international debut with an injury-time strike.
Despite a rousing finish, however, Trapattoni's men were left in little doubt as to the task ahead of them when they return to action in the new year.
Three wins and as many draws from his first six matches, and seven World Cup points from a possible nine, had given the Italian a creditable start to his reign.
But just as a nation started to dream of South Africa 2010, Poland turned up to remind the the 69-year-old and his players, if ever they needed it, that the job has only just begun.
Trapattoni handed senior international debuts to substitutes Andrews and Noel Hunt and a first start to Caleb Folan on a night which saw Kevin Kilbane win his 92nd cap to move into second place in the country's all-time appearance list.
While the manager always intended to use the game to look at some of the emerging members of his squad, he admitted he would have one eye on the result, and to that end, he will have had mixed feelings as he headed for the dressing room at half-time.
Hull striker Folan, deputising for injured skipper Robbie Keane, was a real handful for the Polish defence, and linked nicely with both partner Kevin Doyle and wide-men Duff and Andy Keogh.
However, it was Mariusz Lewandowski who proved the most potent force in either penalty area during the opening 45 minutes.
His third-minute glancing header from Lukasz Gargula's free-kick put his side ahead with Folan unable to prevent him opening the scoring, and the towering midfielder was left criminally unmarked as he met Jacek Krzynowek's 27th-minute corner but this time, could not hit the target.
Indeed, the visitors, roared on by what seemed like a sizeable proportion of the Polish community currently living in Ireland, might have had the game won by the break had lone striker Pawel Brozek not passed up a golden opportunity five minutes before the break.
Richard Dunne, who had dashed back to Manchester to be with his pregnant wife last night before returning to Dublin on the afternoon of the match, miscued a clearance into Brozek's path, but then recovered superbly to dispossess him before he could shoot.
But for all Poland's impressive play going forward, they too looked vulnerable at the back, and they were grateful that Duff had left his shooting boots back on Tyneside.
He lifted a fifth-minute right-foot shot high over after Doyle and Folan had created space for him, and then fired wastefully into the side-netting as he ran on to Doyle's 29th-minute pass.
Duff did well to work his way into a shooting position after combining well with Folan two minutes before the break, but he slipped as he went for goal and skewed his effort well wide.
Beenhakker made two changes at the break and one of the new arrivals, Guerreiro, wasted little time in making an impact.
The Brazilian-born midfielder had only been only the pitch a little more than a minute when he ran on to Gargula's flick and dispatched a left-foot shot emphatically past Shay Given and into the bottom corner.
It should have been 3-0 with 59 minutes gone when Robert Lewandowski fired wide from close range, although the fireworks were still to come.
Trapattoni made five second-half substitutions and Beenhakker four, and the result was explosive.
Alex Bruce headed just over and Shane Long saw a looping effort cleared off the line by defender Dariusz Dudka, and Ireland's reward finally came with two minutes remaining when Stephen Hunt converted from the spot after Long had been felled by Tomasz Jodlowiec.
Robert Lewandowski's 89th-minute strike killed the Irish celebrations in their infancy, but Andrews left his mark on an astonishing end to the game in injury-time.