The 47-year-old suffered a double defeat against Racing in the pool stages, where the Tigers were beaten 22-18 in Paris before a 23-20 loss at Welford Road.
The former Leinster head coach said the Irish province would have to be accurate in defence if they are to win the European Cup for a fourth time.
Speaking on the EPCR European Rugby Show, O’Connor said of Racing: “I think what we saw in the first 30 minutes (against Munster) is that if you are not incredibly accurate defensively, they have got a lot of points in them. So Leinster will have to be a little bit more accurate and show that defensive energy that they have shown throughout the tournament.
“They [Racing] have the ability to go through the gears quickly and score points.
“In the away game in France we were quite comfortable for large parts of it, but they scored three tries in the blink of an eye and it changed the nature of the game. [Maxime] Machenaud is huge, though, so his injury is very significant. He is a different level for me.”
O’Connor believes Leo Cullen’s troops have the experience and ability to come out on top this weekend.
“That has been the best aspect of Leinster’s play this year. In the quarter-final against Saracens they were immense defensively and the same in the semi-final. They have played a lot of knockout rugby against a lot of big French sides, so they will be adept at understanding what they have got to deliver and I will be surprised if they don’t deliver this time around.”
The Australian also heaped praise on the roles played by fly-half Johnny Sexton, captain Isa Nacewa, and head coach Cullen.
“What they are doing is playing a fantastic brand of rugby with a really good squad,” said O’Connor.
He has got some great leaders in Johnny and Isa and the energy and youth is feeding off that.
Meanwhile, the Wallabies have full faith that injured star Will Genia will recover in time for next month’s Test series against Ireland but are looking at one of his Melbourne Rebels teammates as a back-up.
Wallabies assistant coach Stephen Larkham says Michael Ruru is in the selection mix, turning up the heat on his Super Rugby clash with Brumbies No.9 and Test incumbent Joe Powell in Canberra tomorrow night.
Larkham says he’s certain Genia will recover from his knee injury in time to face the Six Nations champions, with the first Test in Brisbane on June 9.
“We’ll have to see how the rehab progresses but I’m 100% confident (he’ll play),” said Larkham.
“Without putting a time frame on it, I think there’s the potential to play some Super Rugby before we get to the Test season.”
Kiwi-born Ruru only made his Super Rugby debut with the Western Force last season but the 27-year-old has impressed with his physicality, with his Rebels coach Dave Wessels earlier this season saying he has some “pig dog” about him.
Long-time Genia understudy Nick Phipps can also press his claims this weekend after being named for his first start of the season against the table-topping Crusaders in Christchurch.
“At the moment, there’s a few guys putting their hands up,” said Larkham.
“Down in Melbourne, there’s obviously Michael Ruru, who has been on the radar for a while so it will be interesting to watch his next couple of rounds.
“Then there’s Nick Phipps, who is coming back into the Waratahs set-up, Jake Gordon’s been playing some really good football there and Joe Powell is sort of the incumbent from the tour last year.”