At least he could claim his decision to make seven changes made no difference to the outcome. But that was helped by Blackburn counterpart Sam Allardyce doing even more to undermine the status of the oldest knockout competition in football.
On target: Aston Villa's Nathan Delfouneso opens the scoring
Allardyce made nine changes to his line-up, then defended himself bysaying: 'The Carling Cup normally sits behind the FA Cup but we have togive ourselves the biggest chance in the semi-final and we need to getour noses in front on Tuesday.
'That's why I made the changes and some of the big players didn'tplay.' T he result was that Allardyce could only watch as his centraldefence crumbled and fell behind to headers so casually unchallengedthat many a grandparent could have done the finishing.
As it happened, Nathan Delfouneso and Carlos Cuellar executed theeffortless work in front of goal, both teed up by Ashley Youngset-pieces.
When Rovers midfielder El-Hadji Diouf crashed crazily through theback of fellow Senegalese Habib Beye late in the first half,and referee Howard Webb showed him a straight red card, thecontest might have been over.
Sportingly, Beye had tried to save his compatriot with a conciliatory arm, but the Yorkshire official was having none of it.
Diouf will miss Tuesday's first leg and a disgruntled Allardyceinsisted: 'They will justify it by saying it was two-footed but I see alot of those type of tackles not punished with a sending-off. Thereferee was a long way away, and I don't think his assistant made thedecision - the crowd did.'
Sheer delight: Martin O'Neil celebrates the opening goal for Villa
Rovers had already shot themselves in the foot when Steven Reid wasbrought down by Nigel Reo-Coker, and David Dunn allowed Villa keeperBrad Guzan to save the penalty with an agile dive to his left.
Guzan's heroics in the Carling Cup at Sunderland - one saved in thegame, three in the shoot-out - were apparently no flash in the pan.
'You almost expect him to save penalties these days, though that is a little unfair,' said O'Neill.
We're going through: Aston Villa's Carlos Cuellar (right) celebrates scoring the second goal with ames Collins
Allardyce admitted: 'It went from bad to worse in the first half andwe left ourselves with such an uphill struggle that we couldn't getback to where we wanted to be.'
They nearly managed it. Guzan fumbled Rovers substitute Morten GamstPedersen's 55th-minute dead-ball delivery. N ikola Kalinic punished theerror to halve the deficit and should have drawn his side level, onlyto fire wide instead. O'Neill was unhappy about that.
'We were sloppy in the second half,' he admitted. 'Maybe we thoughtwe were home and dry.' R overs Reserves were finally killed off whentheir captain, Gael Givet, fouled Villa substitute John Carew.
On the spot: ohn Carew nets Villa's third with a penalty
The Norway striker converted the penalty with ease. But thematch was shabby and expressionless. The favoured fixture on Tuesdaynight will surely be more keenly fought. O'Neill's men should have wonby more.
Young was clean through in the first half but could not beat JasonBrown. And Emile Heskey was robbed after the interval by Givet with anopen goal beckoning.
Villa had failed to negotiate the third round in six of the past eight years, so at least they improved on that sorry statistic.
More FA Cup reportsBolton 4 Lincoln 0: It's all too easy in the cup for managerless TrottersNottingham Forest 0 Birmingham City 0: Earnshaw pays the penaltyPortsmouth 1 Coventry City 1: Pompey show plenty of spirit as Sky Blues earn replayMilton Keynes 1 Burnley 2: Alexander and Fletcher on target as Clarets winTottenham 4 Peterborough 0: Kranjcar double for Spurs punishes PoshSunderland 3 Barrow 0: Malbranque and Campbell put non-leaguers outMiddlesbrough 0 Man City 1: Benjani strikes to send City into fourth roundEverton 3 Carlisle 1: Cumbrians go down fighting at Goodison Park