An impressive defensive stand and an inspired Johnny Sexton guided record four-time winners Leinster to a 13-6 victory at Lyon in the European Champions Cup on Saturday.
Last year's runners up remain unbeaten in Pool 1 and move above former winners Northampton, who beat Treviso 35-32, to top the standings as the French side remain winless in just their second season in the top-tier competition.
Leinster head coach Leo Cullen made five changes from last weekend's victory over the Italians in their opening game of the campaign by handing starts to Ireland internationals Rob Kearney, Robbie Henshaw and Tadhg Furlong.
Lyon's Pierre Mignoni was without Fiji winger Josua Tuisova who is suffering from an ankle injury.
Sexton opened the scoring with a long-range penalty goal after nine minutes as Virgile Bruni was pinned for a high tackle.
The Top 14 league leaders, unbeaten at home since March, dominated possession but their attack was impacted by the greasy surface and a solid Leinster defence.
Cullen's men scored their only try of proceedings after 22 minutes.
Josh van der Flier charged down a Jonathan Wisniewski kick and the visitors played through the phases before No. 8 Deegan crashed over.
Five minutes later Ireland's Jordan Larmour was shown a yellow card after infringing at a ruck as the hosts counter-attacked.
Lyon spent the remainder of the half inside Leinster's 22 metre but failed to break through disciplined Irish tackling.
Tensions heated early into the second half after Sexton remained on the field after the referee asked his video official for a second opinion on a high tackle from the fly-half but he remained in the field.
After more than an hour of pressure and continuing to control possession the home side were on the scoreboard as Jonathan Wisniewski slotted a penalty.
The visitors made it into Lyon's 22m for the first time of the second half after 75 minutes but Sexton's try was chalked off by the video referee from crossing.
The outside-half then kicked his second three-pointer of proceedings with three minutes to go before Wisniewski slotted one to clinch a late defensive bonus point.
Earlier on Saturday, title holders Saracens hammered Welsh region the Ospreys 44-3 in their first home fixture since they were handed a £5 million ($6.5 million) fine and docked 35 points for breaching Premiership Rugby's salary cap rules.