If this long and eventful rugby season has had a common theme it is that the cream rises to the top eventually. Leinster and Toulouse are not in this weekend’s Investec Champions Cup final by accident and the team sheet is sprinkled with more than enough quality to match the soaring backdrop that is Tottenham Hotspur Stadium. The FA Cup final at Wembley is far from the only big show in town.

As the two sides went through their eve-of-game motions on the most pristine surface imaginable – no stray dandelions or daisies here – it was hard to recall a potentially glossier club rugby finale. The showdown between the respective powerhouses of Ireland and France is set to attract the biggest attendance at this fixture for 10 years and the tingle of collective anticipation has rarely been stronger.

There is, however, a nagging question hanging in the bright north London air. Will this prove third time lucky for Leinster after two agonising final defeats to French opposition in the past two seasons, or will Toulouse simply prove too good? Given the supposedly high-achieving Irish province have prevailed in this tournament only once since 2012, another loss would be a major psychological blow.

Related: Dupont or Gibson-Park at scrum-half in my fantasy team? There’s no contest | Ugo Monye

And while on paper they have a good recent record against these opponents there is no home-ground advantage this time, nor the same unshakable sense of certainty. Toulouse are bang in form and primed for the challenge of becoming the first club in European history to claim this title six times. They have the peerless Antoine Dupont, the weather is set fair and at their best their powerful forwards and incisive backs can leave spectacular vapour trails.

En route to the final they have racked up 133 points against Racing 92, Exeter and Harlequins in the knockout stages alone and, as their towering French international lock Emmanuel Meafou made clear this week, the mood within the camp has shifted accordingly. “We like our chances this time,” said Meafou, brushing aside his team’s brace of semi-final defeats to Leinster in Dublin in the past two seasons. “The boys are up for it.”

The onus, consequently, is on Leinster’s defence, orchestrated by South Africa’s World Cup-winning coach Jacques Nienaber, to stand firm against the rouge et noir tide. The idea of hiring the high-achieving Springbok guru was to help win them this type of big, intense game and the acid test of his remodelled blitz defensive system is nigh.

Because if you offer these opponents a glimmer of midfield attacking space there will be big trouble. No northern hemisphere team offloads with the same natural insouciance as Toulouse, regardless of the number on their jerseys, and their bench strength was ultimately too much for Chiefs and Quins.

Which goes a long way towards explaining Leinster’s deliberate team selection. A 6-2 forward-dominated bench, including the seasoned Irish internationals James Ryan and Josh van der Flier, looks designed to ensure the doughtiest combination is on the field for the last 20 minutes when, if recent finals are any guide, the game will be decisively shaped.

Nienaber presided over South Africa’s sequence of three consecutive one-point victories to win the World Cup last autumn and he has been drumming into Leinster’s players the importance of hanging tough when the game’s momentum is flowing against them. “Unfortunately there is no magic pill,” said Ryan, among those keen to atone for previous heartbreaks. “But it’s about staying in the fight for the full 80 minutes and making everything a contest. That’s the way he looks at it.”

Leinster’s director of rugby, Leo Cullen, has also spent long enough poring over the last two painful finals against La Rochelle to know what his side cannot afford to do. Last year, in a classic encounter in Dublin, Leinster made a fabulous start only to be reeled in from 17-0 up and ultimately edged out 27-26 by Ronan O’Gara’s streetwise forwards. In the biggest games there have been instances of bigger, stronger packs outlasting them.

It has left Cullen with a tricky balancing act: whether to use the past as a motivation or to absorb its lessons and move on. “I’m not sure there is that much relevance,” he said, only for his captain, Caelan Doris, sitting next to him, to acknowledge the “hurt” of the past two years was very much part of the squad’s emotional mix. “You don’t want to feel that again,” said Doris, such a key figure for both province and country. “We spoke about it at the start of the week; about casting our minds back to that post-game feeling in the last two years and how you’d give anything to have this opportunity again.”

Several members of Toulouse’s side also have in mind their quarter-final defeat at their own World Cup courtesy of Nienaber and friends. Their coach, Ugo Mola, suggests there is a feeling of “good karma” among his players but they have been leaving little to chance having brought in the French international referee Mathieu Raynal to help their preparations. “If we’re not disciplined it will be very hard,” Dupont said.

For both sides, though, the relatively narrow pitch and shallow in-goal areas will require a little adjustment. With the playing surface also on the firm side there may be a greater chance of long, aimless kicks running dead. It may also mean less space out wide, putting more onus on both sets of half-backs to pick the right options.

Either way it will be some occasion, not least for young Joshua Brennan, son of the former Irish international Trevor Brennan who owns a Toulouse bar. Scotland’s Blair Kinghorn has again been chosen ahead of Thomas Ramos at full-back although the latter, one of Europe’s deadliest kickers, could still have an important role to play late on.

Potentially career-defining days loom, too, for Jason Jenkins and Will Connors, picked to start ahead of Ryan and Van der Flier with the obvious intention of not giving Toulouse time to settle.

One look at Dupont’s steely pre-match expression underlined just how hard it will be for Leinster to deny the world’s pre-eminent player. Spurs fans already know what a top-class No 9 looks like and there is every chance of Toulouse’s talisman dashing Leinster dreams once again.