Australia lock Will Skelton said La Rochelle will have a "real old crack" as they host joint-record four-time winners Leinster in their first European Champions Cup semi-final on Sunday.
Skelton, 28, joined the French club, who were still playing in the second-tier seven years ago, this season after winning the title twice in four campaigns with Saracens.
"If we can avoid the game overwhelming us we can give it a real old crack and really shake up this competition," he told AFP.
"We're excited for the history of the club. This new generation of this club has been coached not to know our limits. There is no ceiling there," he added.
The Top 14 side are led by former New Zealand loose forward Jono Gibbes, who announced last week he would be leaving the club for Clermont at the end of the campaign.
Head coach and ex-Ireland fly-half Ronan O'Gara, who also won the European Cup twice, with Munster, will be promoted to director of rugby after Gibbes' departure.
"Him and Jono have been awesome for the team, with our direction and really getting us prepared for the way we want to play," Skelton said.
O'Gara, as well as his double trophy success, is the Champions Cup's leading points scorer and has the most appearances for a player in the tournament.
Skelton said La Rochelle's fly-halves including ex-Maori All Blacks playmaker Ihaia West can turn to O'Gara for words of wisdom.
"He's got experience, he's played in big matches, one of the clutch players of his generation," Skelton said.
"We're very lucky that we've got Ronan, who has been there and done it. We can lean on him, especially our 10s," he added.
- 'Great Wallaby' Fardy -
This weekend Skelton, who still hopes to add to his 18 Wallabies caps, will face former Test team-mate Scott Fardy.
Earlier this month, loose forward Fardy announced he will retire at the end of the season aged 36 after 39 international appearances and already has a Champions Cup winner's medal to his name.
"I played a few years with 'Fards'. He's a great player and a great Wallaby," Skelton said.
"It will be good to catch up with him and see how he goes. Hopefully he doesn't play too well against us. He's had a wonderful career in the game," he added.
In the other last four tie, Toulouse, who have also won the competition on four occasions, host Bordeaux-Begles, who are making their first appearance in this stage of the tournament.
Saturday's visitors were forced to postpone two league games due to Covid-19 cases among their squad and have only trained as a squad this week since the quarter-final win over Racing 92 on April 11.
"It's more difficult for them, obviously. Covid, it's rubbish for everyone, not just rugby. They haven't been lucky," Toulouse captain Julien Marchand said on Thursday.
Fixtures (times 1400GMT)
Toulouse v Bordeaux-Begles
La Rochelle v Leinster