A poor opening half of rugby on a heavy pitch, that had been blitzed by torrential rain prior to kick-off, saw the Italians take control early on and grow into a 12-3 lead.
Former All Black Brendon Leonard gave the hosts a dream start on three minutes as he pounced on a loose ball in the drizzle before a second try from GiulioToniolatti, after a horror kick off the greasy turf evaded Blues.
Gareth Davies slotted the only points for under-par Blues, with Rory Watts-Jones and fellow flanker Flippo Ferrarini both yellow carded in an error strewn opening half.
An early second half try from Tom Williams sparked comeback hopes for Blues before late drama as Robinson crashed over with the last move of the match with time up.
Blues celebrated the score but, after a lengthy consultation with the TMO, the score was chalked off for obstruction to the dismay of the visitors who felt they had claimed at very least a draw and had a kick to win the game. Instead, only a losing bonus point was taken.
Zebre, who had stunned Blues at the Arms Park earlier in the season, looked to play from the opening minute and a clever low grubber kick in behind was collected by Robinson, but he had no choice but to slide into touch as momentum took him skidding across the soggy turf.
A big first home scrum paid dividends as the ball was run-up close by giant Number Eight Samuela Vunisa before, when it popped loose, the ever-alert scrum half Leonard scooped up dived over the line. The referee went to the TMO before awarding the try, despite calls for a knock on in the build-up.
Blues hit back with a well-struck penalty from Davies while home kicker Kelli Haimona pulled an effort of his own wide of the target as the home fly half had a ten-minute spell to forget.
Twice Haimona missed kickable opportunities from in front, with his second falling well short in the rain, but Blues problems with the officials were only mounting after a succession of penalties.
The referee finally lost his patience and yellow carded Watts-Jones on 16 minutes as Blues were hit for dragging down a driving maul. Zebre immediately went for a second try with the numerical advantage, only to knock on ball within sight of the line.
The Italians, though, did not have to wait much longer, although their second scored owed much to a slice of fortune. An innocuous kick ahead looked to cause no harm, only for it to spit up horribly, evade Tom Williams and fall into the grateful hands of Toniolatti who dived over unopposed.
Blues needed to respond to the two-try blow and a kick to the corner set up a series of driving lineouts. Zebre also lost a man to the sin bin, with Toniolatti yellow carded for dragging down a maul. But the visitors could not take advantage as the soap like ball was lost inches from the whitewash.
A sustained period of aerial ping pong saw Dan Fish win the territory battle with a superb kick to the corner that took a flick of a Zebre hand to hand Blues another attacking platform. But the drive failed to deliver as the visitors failed to hold onto possession once more.
A clever tackle from scrum half Jones around the fringes, as Vunisa lost control at the base, gave Blues one final chance with a minute left on the clock. Gavin Evans made the line break but as Blues switched play left the final ball from Williams saw Dicomidis bundled out.
Blues made one half-time change as Tom Davies replaced the injured Sam Hobbs and the loosehead prop was straight into the thick of the wet and soggy action as he carried down the middle and into contact at pace.
The visitors were trying to squeeze the Italians as they repeatedly kicked into the corner with Fish drilling a low effort to jam Zebre right back in their own 22 and pile on the pressure.
Blues repeatedly pounded the Italian wall of defence before neat handling saw Evans fed Williams on his shoulder on 50 minutes and the full back confidently exploited the gap and dotted down to cut the lead to two points.
A missed penalty by Luciano Orquera, a fourth of the afternoon that was off-target from the home side, gave Blues a reprieve on the hour before Lou Reed made his comeback off the bench.
Zebre finally found their kicking range as Orquera opened up a 15-10 lead with 15 minutes left in the game.
Blues needed a quick-fire response and Robinson nearly produced it as an inside pass from Jones sent him racing into space. Dafydd Hewitt and Ellis Jenkins also carried strongly as the visitors hunted a game-changing score.
A tense and nervy final five minutes saw Fish break clear down the left flank and kick into space ahead. The ball looked set to run for Ellis Jenkins, but a cruel bounce saw it then curl back in field and the young flanker could cruelly not touch down.
One final attack, with time now up, saw Blues go through the phases and then peel down the short side. A slick interchange of passes between Fish and Robinson saw the wing glide over to wild celebrations. But, after consulting the TMO for several minutes, the try was controversially chalked off to hand the Italians the win.
Timeline:
03m Leonard t Haimona c 7-0
07m Davies p 7-3
22m Toniolatti t 12-3
50m Williams t Davies c 12-10
64m Orquera p 15-10
Cardiff Blues: 15 Tom Williams, 14 Harry Robinson, 13 Isaia Tuifua (Hewitt 64), 12 Gavin Evans, 11 Dan Fish, 10 Gareth Davies, 9 Lewis Jones; 1 Sam Hobbs (Davies 40), 2 Kristian Dacey (Williams 61), 3 Scott Andrews, 4 Chris Dicomidis (Reed 61), 5 Filo Paulo, 6 Rory Watts-Jones, 7 Josh Navidi, 8 Robin Copeland
Replacements: 16 Rhys Williams, 17 Thomas Davies, 18 Beniot Bourrust, 19 Lou Reed, 20 Ellis Jenkins, 21 Tomos Williams, 22 Simon Humberstone, 23 Dafydd Hewitt