But after the break Leinster's dominance finally told and Luke Fitzgerald went over twice before Jordi Murphy dotted down at the death to secure a bonus point.
The 27-0 victory keeps Leinster atop the RaboDirect PRO12 table and the extra point could prove critical with just five regular season games remaining - a point not lost on O'Connor.
"The five points were important. It was very stop-start, we struggled to get momentum at times in the game and there was an interesting interpretation of the scrum," he said.
"We had enough ball, but we didn't get it at the pace that we needed it. We finished strongly though and got the four tries, took the points and nobody was injured, so those are the positives.
"The five points are invaluable and it keeps our noses in front [at the top of the table]. It's season-defining stuff in the next few weeks and everyone's very focused on what's ahead."