Leinster survived a strong comeback from opponents Zebre to prevail 33-29 in their opening United Rugby Championship game of the new season.

Last season's bottom side fought back and their five tries, plus their four-point deficit, ensured that they secured two bonus points of their own.

In the end, a relieved Leinster clung on to run out four-point victors.

Zebre, who won only one of their 18 URC games last season, fell just short of a first ever victory over Leinster after their outstanding second-half display at Stadio Sergio Lanfranchi.

Tries from Luke McGrath, Rhys Ruddock (2) and Jason Jenkins put last year's table-toppers Leinster in control at the interval, 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 although they ended up on the wrong end of the scoreline, their performance 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.

Zebre: Kriel, Bruno, Cronje, Lucchin, Gesi, Eden, Cook, Buonfiglio, Du Toit, Nocera, Sisi, Krumov, Andreani, Pelser, Fox-Matamua.

Replacements: Bigi, Pitinari, Hasa, Furno, Volpi, Fusco, Smith, Trulla.

Leinster: O'Reilly: Russell, Osborne, Ngatai, Kearney; R Byrne, McGrath; E Byrne, Kelleher, Ala'alatoa; Molony, Jenkins; Ruddock, Penny, Deegan.

Replacements: McKee, Milne, Abdaladze, Deeny, Soroka, N McCarthy, Frawley, Conners.

Referee: Ben Blain (SRU)