Despite being on the back foot for nearly the whole of the first half, Scotland managed to get into halftime at 3-3 with Greig Laidlaw’s penalty cancelling out the effort of Mirco Bergamasco, who missed two other kicks.
But Venditti’s try while centre Nick De Luca was in the sin-bin gave Italy an advantage they would not relinquish at a sold out Stadio Olympico.
Laidlaw did reduce the margin with a second penalty but Kris Burton’s late drop goal sealed the win as Scotland suffered a first RBS 6 Nations whitewash since 2004.
While hooker Fabio Ongaro was a late-call up to the Italy XV, prop John Welsh also had to be drafted in for Allan Jacobsen who was withdrawn just before kick-off.
The pressure on both sides to avoid being whitewashed was abundantly clear in a first half which was littered with mistakes.
It was Italy who dominated territory and possession in the opening 40 minutes but their first opportunity for points disappeared when a penalty was reversed for an offence by Ongaro.
Italy though continued to make some inroads into the Scottish half with full-back Andrea Masi particularly prominent and when Jim Hamilton came offside at a ruck, Bergamasco took advantage to slot the resulting penalty.
The visitors were their own worst enemies at times, particularly with their lineout failing to function and it was symbolic of their fortunes that in their first visit to the Italian 22, hooker Ross Ford missed his jumpers.
The Azzurri however could not capitalise on their superiority with Bergamasco off target with a penalty before Burton’s drop-goal attempt was charged down by John Barclay.
And they were punished on 35 minutes when Italy conceded a penalty at a scrum and Laidlaw landed a long-range penalty.
Andy Robinson would have been delighted to see his side go in level at halftime on the balance of play but he would have been furious to see De Luca sin-binned for a cynical attempt to kick the ball out of Edoardo Gori’s hands – the only saving grace was Bergamasco again failed to take advantage with the penalty.
Italy came out fired up for the second half determined to take advantage of their numerical superiority and they duly delivered inside the first four minutes.
Having pounded away at the Scottish line through several phases, they worked the ball to the left where Venditti surged past full-back Stuart Hogg to touch down under the posts. Bergamasco could not miss the conversion.
Scotland had the opportunity to respond immediately but Laidlaw just couldn’t bend his kick in from a difficult angle from the right-hand touchline.
Things continued to go from bad to worse for Scotland when De Luca emerged from the bin, only for Hamilton to be sent there in his place after being yellow carded for pulling down a maul.
But when Italy were penalised at a lineout, Laidlaw’s second penalty brought them to within four points on the hour mark.
And the tide continued to turn when Hamilton came out of the bin and Alessandro Zanni replaced him when he was penalised for going in off his feet. But again when Scotland kicked to the corner, Ford’s lineout was off target and the opportunity was gone.
It was becoming an excruciating experience for the Scotland captain with another butchered lineout in the Italian 22 with six minutes to go.
He was made to pay when Burton dropped a goal that helped commence wild celebrations among Brunel’s men and desolation from the visitors.
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