The sell-out game at Thomond Park will see 10 of the Irish Grand Slam side go up against up to nine of the Welsh team they pipped 17-15 at the Millennium Stadium last month.
And the virtual re-run of that thrilling Six Nations finale in the Welsh capital will see the 2005 Lions lock pairing of O'Connell and Donncha O'Callaghan going up against their Welsh rivals Alun-Wyn Jones and Ian Gough once again.
"Lions selection is not something we've thought about in the context of this game. We're just thinking about getting the team through the quarter-finals," said O'Connell.
"If your team performs well then selection will get helped by that. By players thinking only of the team, then the team performs well."
Other potential Lions duels will see Ronan O'Gara go up against James Hook, Ospreys skipper Ryan Jones take on Denis Leamy and Adam Jones go head-to-head with Marcus Horan and John Hayes in the front row battle.
Despite O'Connell's insistence that Sunday is all about reaching the last four of the Heineken Cup, there will be at least one member of the Lions coaching team in Limerick to watch the game.
Head coach Ian McGeechan, who will be at Leicester and then Twickenham over the weekend, is sending his coaching group of Warren Gatland, Shaun Edwards, Rob Howley and Graham Rowntree to take one last look at some of the candidates for his squad this summer.
The Lions party is due to be announced in London on 21 April and McGeechan always said he would use the Heineken Cup quarter-finals as one of his final barometers of form.