Leinster were left clinging on for a 33-29 United Rugby Championship victory over Zebre Parma in Italy after last season's bottom side threatened to pull off their first victory over the Irish province.

Zebre ended the inaugural URC campaign with only one win to their name but they pushed Leinster – who topped the overall standings last term – all the way at Stadio Sergio Lanfranchi thanks to an excellent second-half display.

Tries from Luke McGrath, Rhys Ruddock (2) and Jason Jenkins had given Leinster a 28-10 half-time lead and a try bonus, with Richard Kriel and Pierre Bruno touching down for the home side.

Simone Gesi and MJ Pelser crossed early in the second period as the deficit was reduced to 28-22 and the margin was down to four after Zebre responded to Dave Kearney’s unconverted try with a Franco Smith touchdown.

Zebre pushed for an unlikely victory but had to settle for a pair of bonus points in the end, along with a performance that will give them huge encouragement heading into the rest of the season.

McGrath went over from close range after six minutes as Leinster dominated the opening exchanges, with Ross Byrne adding the conversion.

Ruddock then powered his way through a number of Zebre bodies to add Leinster’s second as the clock hit 20 minutes.

Byrne again added the extras and Zebre then lost captain David Sisi to the sin bin for an accumulation of infringements by the home side.

Ruddock burrowed his way over as Leinster quickly made the extra man count – Byrne again splitting the posts – but out of nowhere Zebre produced a try of real quality.

The hosts spread the ball quickly out to the left wing from a scrum, showing excellent hands and setting up debutant Kriel to go over.

The conversion was missed but Zebre quickly added a second try when Tiff Eden’s kick to the wing was collected by Bruno, who then chased down his own chip forward to score.

Eden was off-target again from the tee and normal service was momentarily resumed when debutant Jenkins secured the bonus point with a powerful finish and Byrne converted.

Zebre started the second half strongly and Gesi stretched for the line in the corner to score his side’s third try before Pelser crashed through Jamie Osborne’s attempted tackle to go over under the posts, with Eden’s conversion – his first successful kick of the match – making it 28-22.

Kearney re-established some daylight but Leinster will have been relieved to escape with the win after Smith’s try – converted by Eden – had them under intense pressure late on.