It should have been thank you and goodnight when Algeria defender Medhi Meniri elbowed Viduka in the face and earned a red card.
But oddly, as everything else starts to fall into place for O'Leary's dream of filling the Elland Road trophy cabinet, their inability to deal with the UEFA Cup, that fast-fading poorer cousin of the Champions League, is the one cause for concern.
Leeds are scheduled to move into a £60million state-of-the-art stadium and they top the Premiership, at least until Manchester United's local dispute with Bolton tomorrow.
O'Leary also no longer shops in the bargain basements for his players, as £9million England Under-21 midfielder Seth Johnson proved when he greeted the fans at half time following his move from Derby. O'Leary himself is just back from midweek high- class window shopping, when he watched Lazio play PSV in Rome and Sparta Prague win in Rotterdam against Feyenoord, whose Aussie midfielder Brett Emerton has long been studied by Leeds' scouting network.
The manager has said that Leeds just need a touch of luck for the breakthrough, and having survived the shakiest of UEFA Cup starts in the first round - when unfancied Maritimo beat them 1-0 in Madeira against the odds - Leeds might need a little more fortune in Troyes.
They will certainly need their wits in Champagne country if the resilience of Troyes - and the striking instinct of Loko - come to the fore in two weeks' time, even though at times last night the French looked nowhere near as dangerous as the modest Portuguese had been.
But appearances can be deceptive, as Newcastle warned after being turfed out of the InterToto Cup at St James' Park when Troyes earned an unlikely 4-4 draw.
For all the excitement of Leeds' attacking style and the goals generated, it was Loko's double that mattered most.
Matteo was the defender caught out both times, but just as at Old Trafford the previous evening there was a case for examining the defending as a team, with Leeds vulnerable to the breaks that the French, down to 10 men, saw as their only salvation.
Bowyer, who as he did last season raced from a court case in Hull to play an outstanding game, did not deserve to have his night muted. Nor did reinvigorated Viduka, who looked so sharp a hat- trick often appeared a near certainty.
Substitute Alan Smith almost restored the threegoal cushion in injury time, but the England striker was surrounded by a pack of defenders as he tried to get round goalkeeper Tony Heurtebis. It was a warning of the challenge to come.
