The result added yet another dark chapter to South African rugby history which was shaken right down to its foundations when they succumbed to Japan at last year's World Cup.
It was a thoroughly depressing display by the Boks and there is now a real possibly that they could go winless on this three-Test tour after they were humiliated by England last week. Next week Wales lie in wait at the Millennium Stadium.
Italy showed encouraging touches at the start when they retained possession through multiple phases and then once the flow of play was reversed they were equally impressive on defence.
However, as the Boks' early attacks picked up on intensity, their backline showed some deft touches on an eighth-minute sortie in Italy's 22m area and Habana went over in the corner - he's 67th Test try - for an unconverted touchdown. (5-0).
Italy's response was kickstarted by a penalty which they kicked to touch to set up a 5m lineout, which they made good. Italy's SA-born lock Dries van Schalkwyk (a former Cheetah) drove through the middle of a powerful driving maul to score.
Carlo Canna, Italy's flyhalf, converted to give Italy a 7-5 lead.
A 16th-minute turn-over for the Boks deep inside their own half presented a counter-attack opportunity which was sprung by the collective efforts of flyhalf Pat Lambie and fullback Willie le Roux. Centre Damian de Allende cantered in near the corner flag to round off a great break-out from South Africa's 22m area.
This time Lambie was on target with the conversion attempt and the Boks were back in the lead at 12-7 in the 17th minute.
A 30th scrum penalty gave Italy a chance to reach double figures as fullback Edoardo Padovani sent the ball through the posts to reduce the deficit to two points (12-10).
As play approached the halftime break, Le Roux and rightwing Ruan Combrinck initiated attacking plays deep into the Italy half with sparkling individual efforts but Italy's defence prevented further damage with solid defence and effective, yet questionable, slowing down tactics at the breakdown points.
The Boks continued where they left off when second-half play resumed and a minute later Italy was reduced to 14 players when their lock Marco Fuser was yellow-carded for taking out his opposite number Lood de Jager while he was taking the ball above the line-out.
From the 5m line-out which followed, the Boks waged a wave of predictable pick-and-goes which Italy thwarted and eventually it was left to Lambie to make good the ascendency with a penalty in front of the posts (15-10). In the 52nd minute, the Boks sent on a raft of substitutes as Steven Kitshoff, Trevor Nyakane, Faf de Klerk and Elton Jantjies joined the fray.
The changes did not make an impact and the Boks, very much against the run of play, found themselves in arrears five minutes later when Italy's brute strength upfront paved the way for leftwing Giovanbattista Venditti to cross out wide when he flattened Janjties with a handed-off.
Canna converted to regain the lead for Italy (17-15). Just past the hour mark, Jantjies and Canna were each on target with penalty attempts as Italy retained the slender two-point lead in the 65th minute (20-18).
In their desperation to save the game, the Boks looked less than average as they battled to cope with the pressure and although they enjoyed sufficient they were unable to set up any threatening moves in Italy's half.
Having successfully looked after their two-point cushion Italy launched one final attack on the Bok tryline and they came close two minutes from the end when their ball-carrier was adjudged to have a foot in touch as he was driven over the whitewash by the powerful Italy forward unit.
A 5m line-out, a minute ahead of the final whistle offered the Boks one last chance to rescue the match but they lost that too and that just about summed up yet another miserable day for Springbok rugby.
Scorers: Italy 20 (10): Tries: Dries van Schalkwyk, Giovanbattista Venditti. Conversions: Carlo Canna (2). Penalties: Edoardo Padovani, Canna South Africa 18 (12): Tries: Bryan Habana, Damian de Allende. Conversion: Pat Lambie. Penalties: Lambie, Elton Jantjies
African News Agency (ANA)
Original source: Another dark day for Springbok rugby