Trapattoni's decision to hand striker Jonathan Walters a Euro 2012 play-off mission paid off in style as the Stoke forward, making his first competitive start for his country at the A Le Coq Arena, opened his goalscoring account as the Republic routed nine-man Estonia to take a massive stride towards next summer's finals.
Trapattoni waited until the last moment to name Walters in the team ahead of West Brom's Simon Cox having hinted earlier in the week that that was what he might do, and his faith was fully repaid.
He said: "I'm not God, I don't speak English very well - I don't speak Italian very well - and I make many mistakes.
"But after 30 years in football, I think I understand it a little bit.
"For this game and on this pitch, I thought Jon Walters would be important to defend the ball and help the team to come up the pitch.
"Jon showed his quality. We got it right."
Ireland got most things right as they surged to their biggest competitive win under Trapattoni and Estonia's hopes were torn apart in cruel fashion.
They were already trailing to Keith Andrews' 13th-minute header when central defender Andrei Stepanov was booked for a second time and sent off.
But they found themselves 3-0 down to Walters' 67th-minute header and Robbie Keane's close-range finish four minutes later before skipper Raio Piiroja joined Stepanov in the dressing room as a result of two cautions in quick succession.
Both will miss Tuesday night's return in Dublin, as will keeper Sergei Pareiko, who will be suspended as a result of the yellow card he was given for protesting at referee Viktor Kassai's decision to award an 88th-minute penalty for Ats Purje's trip on fellow substitute Stephen Hunt.
Keane took his international tally to 53 from the spot to seal a thumping victory.
Trapattoni said: "It will be important in Ireland to confirm the result because there are another 90 minutes to go.
"In those other 90 minutes, we will respect our opponents. They will come with a different mentality, a different attitude and a different performance.
"We must repeat our performance."
It proved a sobering night in Tallinn for Estonia boss Tarmo Ruutli, whose best-laid plans were ripped up long before half-time.
Asked if the tie was over, he said: "Almost".
Asked further about the role the referee's decisions had played in the game, he said: "Of course they played some part in the result, but the first two goals, they were our problem, not the referee's problem."