The Italian looked on for the second time in four days as his players claimed the scalp of a side which, unlike them, will head for South Africa next month.

Ireland's fate was sealed in controversial circumstances in Paris in November, but ever since then the 71-year-old has been focussed on the next challenge, that of qualifying for Euro 2012.

On the evidence of what he saw against Paraguay on Tuesday and again tonight, Trapattoni insisted the Republic will not miss out for a second time under his charge.

He said: "If we play like we did against Paraguay and Algeria, I think we must achieve qualification for the European Championships."

The Algerians, backed by a raucous travelling support at the RDS, were systematically dismantled by Ireland, who took full advantage of the absence of several of their better players.

The took the lead after 32 minutes when Derby midfield Paul Green, making a first start for his country after being handed a debut as a substitute against Paraguay, dived to head home Liam Lawrence's cross.

Algeria rarely threatened to drag themselves back into the game and fell further behind seven minutes after the restart when skipper Robbie Keane made the most of errors by full-back Aldane Guedioura and keeper Faouzi Chaouchi to hook home a second.

Keane might have completed a hat-trick but for Chaouchi, a post and substitute keeper Rais Mbolhi.

But he did register for the 43rd time in his senior international career five minutes from time when, after he had been tripped by defender Djamel Mesbah, he converted the resulting spot-kick.

The victory was Ireland's biggest to date under their new manager, and may go some way towards appeasing the critics who have accused the veteran boss of adopting a negative approach to his job.

It was a fitting way for the Republic to end a season which has brought both progress and heartbreaking disappointment, and Trapattoni was able to take plenty of positives, not least from the performances of Green and 19-year-old debutant Greg Cunningham.

He said: "We started the game with conviction and Paul Green and Greg Cunningham played without fear.

"I asked the senior players to watch them, but they didn't need any help.

"When I closed my eyes, Cunningham could have been any left-back, Green too.

"They were fantastic and we did not miss any players we did not have tonight.

"Robbie Keane, Damien Duff and Kevin Doyle, are the pillars of our side and were outstanding."

Opposite number Rabah Saadane's night in Dublin proved a sobering experience in front of the watching Franco Baldini, England boss Fabio Capello's right-hand man.

The two side's will meet in Cape Town on June 18 in Group C, and Saadane knows his team will have to perform significantly better if they are to have any chance of taking something from the game.

He said: "Ireland are a formidable team - they were superior to us and deserve a place in the World Cup.

"But England will be a tougher team than the one we faced tonight. They are one of my favourites to reach the final."