Ulster needed a dubious penalty try in the dying minutes to edge past Zebre 27-25 in Sunday's PRO12 clash in Parma.
Ulster maintained their unbeaten start to the season to remain top of the Pro12, but only by the skin of their teeth.
In this rearranged fixture, which was scheduled following the Nevin Spence tragedy in September, the league leaders had to utilise their full quotient of mental strength to emerge victorious.
With the Treviso fixture looming on Friday, the Ulster management decided to remain in Italy making this visit, to all intents and purposes, a mini-tour.
Ulster started in the game in determined fashion, displaying an intention to pursue an expansive game and bring their broken field runners into play.
Ulster's forwards endeavoured to bring the ball carrying intensity, which has been so apparent thus far this season. The league leaders conceded far too many penalties early on, however, and allowed Zebre to secure a foothold in the game.
It was Ulster, though; who opened the scoring on ten minutes when Niall O'Connor kicked a penalty after the Zebre defence had been caught offside.
The home team bounced straight back and after Ulster were caught napping at the restart, an incredulous Tebaldi nipped in to score.
Ulster increased the pressure thereafter, but were unable to convert possession into scoring opportunities. It was clear that Zebre were determined not to be mere canon fodder, as clearly demonstrated at the breakdown, which was being fiercely contested.
Another O'Connor penalty on 26 minutes re-established Ulster's lead, and made it 6-3 to the visitors. By this stage, Ulster's well drilled defensive unit were beginning to pin Zebre back in their own 22.
An O'Connor penalty on 34 minutes made it 9-5 to the visitors. Slowly but surely, however, the home team were beginning to find their attacking momentum. Zebre came rushing back at Ulster, and some concerted pressure saw Halangahu respond with a penalty on the stroke of half time.
Ulster were determined to press home their scrimmaging advantage, but it was Zebre who began the second half the stronger and Halangahu scored a try on 43 minutes, having negotiated some appalling Ulster defence.
Ulster responded immediately and a good scrum on 48 minutes saw O'Connor land another penalty to make it 13-12 to the Italians.
The home back row was now in the ascendancy and the huge South African Dries Van Schalkwyk extended their lead on 53 minutes. U
llster's unbeaten record was now in real jeopardy. Paddy Wallace scored on 57 minutes to offer some hope. Van Schalkwyk seemed to have killed the game on 65 minutes when he completed his brace, bursting though the non-existent Ulster back row defence.
Incredibly, the Italian minnows were on the verge of a bonus point victory. Ulster were their own worst enemies, and made some horrendous errors with their restarts.
But, not for the first time this season, their pack dug them out of a hole. A destructive scrum on 74 minutes saw referee Neil Patterson award a dubious penalty try.
In the final minutes Zebre tried desperately to secure the win they thoroughly deserved. But Ulster's tenacious defence held on.
Ulster may have won again, but it was their worst performance of the season. Fortuitous indeed, but it was Zebre who came within minutes of making Pro 12 history.
Tries: Tebaldi, Halangahu, van Schalkwyk 2
Yellow cards: Pratichetti
Tries: Wallace, Penalty try
Pens: O'Connor 5
Zebre: 15 David Odiete, 14 Leonardo Sarto, 13 Matteo Pratichetti, 12 Samuele Pace, 11 Alessandro Castagnoli, 10 Daniel Halangahu, 9 Tito Tebaldi, 8 Dries van Schalkwyk, 7 Filippo Cristiano, 6 Filippo Ferrarini, 5 Josh Sole, 4 Filippo Cazzola, 3 Luca Redolfini, 2 Andrea Manici, 1 Matias AgueroReplacements: 16 Andrea de Marchi, 17 Salvatore Perugini, 18 Flavio Tripodi, 19 Emiliano Caffini, 20 Nicola Belardo, 21 Alberto Chillon, 22 Ross McCann, 23 Nicola Cattina.
Ulster: 15 Ricky Andrew, 14 Mike Allen, 13 Jared Payne, 12 Paddy Wallace, 11 Chris Cochrane, 10 Niall O'Connor, 9 Michael Heaney, 8 Roger Wilson, 7 Mike McComish, 6 Nick Williams, 5 Neil McComb, 4 Robbie Diack, 3 John Afoa, 2 Nigel Brady, 1 Callum Black. Replacements: 16 Rob Herring, 17 Tom Court, 18 Declan Fitzpatrick, 19 James Simpson, 20 Alistair Birch, 21 Blane McIlroy, 22 Stuart Olding, 23 Peter Nelson.
By Rory McGimpsey