Ross Byrne’s 19th-minute penalty was enough to give Leinster Rugby their fourth successive Guinness PRO14 victory, as Leo Cullen’s men squeezed past Zebre at Stadio Sergio Lanfranchi.

In a game that was largely devoid of clear-cut try-scoring chances, Byrne’s place-kick was enough to keep the defending champions on the right track as they moved three points clear at the top of Conference A.

Although Cullen will be happy that Leinster emerged with another win under their belts, there will be considerable scope for improvement in advance of their home clash with the Dragons next Friday.

As expected, Leinster displayed their intent inside the opening minutes. An extended spell inside the Zebre 22 created attacking momentum and it seemed like only a matter of time before they broke the deadlock.

However, Byrne knocked on a Jamison Gibson-Park pass just shy of the line and Cian Kelleher could not touch down the scrum half’s kick through on 13 minutes. Having suffered a series of heavy opening defeats, Zebre were eager to keep things tight on their home patch.

While Ian Nagle missed out on an early reunion with his former club, ex-Leinster lock Mick Kearney was part of the Zebre pack. Leinster continued to dominate possession as the half wore on and Gibson-Park was held up towards the end of the first quarter.

Nonetheless, the visitors eventually got up and running courtesy of a routine Byrne penalty. Despite it being a richly-deserved lead, Leinster did not always have it their own way in the opening period.

Mattia Bellini’s powerful break edged Zebre into the opposition half and the visitors were relieved to see flanker Johan Meyer losing the flight of the ball on the left wing. Leinster found themselves on the back foot until they gained a turnover penalty.

When number 10 Byrne found touch from a long-range penalty, it presented the province with an ideal platform. Yet, Zebre’s committed defence kept Leinster bay at once again and it took a last-gasp intervention from Adam Byrne to deny them a try on the stroke of half-time.

There was a strong mixture of youthful exuberance and big-game experience within the Leinster forwards and Byrne’s latest kick to touch on the resumption gave them another shot at the whitewash.

Unfortunately, Max Deegan, on his 50th appearance for his native province, could not secure the resulting lineout and Zebre winger Edoardo Padovani was agonising close to gathering Carlo Canna’s cross-field kick in the 45th minute.

The Italians went on to develop a series of multi-phase moves and it took remarkable discipline on Leinster’s part to avoid the concession of a kickable penalty.

In addition to introducing a whole new front row of Bryan Byrne, Michael Milne and Vakh Abdaladze, Caelan Doris replaced Deegan at number 8. Also added to the mix were Ryan Baird, who was making just his second senior appearance for Leinster, Hugh O’Sullivan and Jimmy O’Brien.

These fresh legs were certainly needed against an increasingly dogged Zebre side, who were patient and resourceful with their use of the ball and this left them with a fighting chance of ending their lengthy losing streak in the Championship.

The longer the play progressed, however, the more impressive Leinster’s defence became. They were awarded a last-minute turnover penalty which Ross Byrne punted to touch. After the lineout was secured, O’Sullivan kicked the ball into the stands to bring an end to this cagey affair.

Leinster Rugby returns to the RDS Arena next Friday to take on Dragons. Tickets are on sale now from €25.