Quins head to south-west France after wrapping up Pool Three one game inside the distance and securing a home last-eight tie. They have collected 24 points from a possible 25 so far in defeating Biarritz at home, Connacht (twice) and Zebre (twice), scoring 27 tries.
That try tally is the tournament's best this term, better than either of the only two clubs - Clermont Auvergne and Toulon - who could overhaul them as number one seeds. If Quins win on Friday with a bonus point, then no-one can catch them, but a victory alone should still be enough.
Clermont and Toulon would require bonus-point wins over the Scarlets and Montpellier, respectively, on Saturday, while also scoring a hatful of tries.
Quins boss Conor O'Shea has made three changes from the team that thumped Connacht 47-8 last Saturday.
Jordan Turner-Hall and George Lowe resume their centre partnership instead of Matt Hopper and Tom Casson, while Tom Guest features at number eight in place of Nick Easter. Full-back Mike Brown, meanwhile, will make his 200th first-team appearance.
Biarritz, the 2006 and 2010 beaten Heineken Cup finalists, have an outside chance of securing one of two best runners-up spots that offer quarter-final places, but they would require a bonus-point win and then for other results to work in their favour.
Their team selection suggests they will go for it, though, with France internationals Damien Traille, Dimitri Yachvili, Fabien Barcella and Imanol Harinordoquy among those who start.
"We will do everything to get this qualification, although we know it does not depend on us," Harinordoquy said.
Connacht and Zebre will complete the Pool Three picture when they meet in Galway on Friday night.