IT is one of Leinster's undiluted strengths that they can call on two international class loose-head props for the unrelenting physicality of front-row rugby.
Ireland's Cian Healy is a front-runner for the British & Irish Lions in six months' time. He showed why against The Scarlets with a tour de force.
Leinster can let Healy off the leash, let him explode into action for as long as he can last because Springbok Heinke van der Merwe is a legitimate alternative.
That was the reason behind Healy's replacement at half-time on Saturday. He emptied the tank and a South African tank was on hand to carry on the good work.
"There was a massive workload from Cian in that first half. He was immense. I thought it was one of the better ones he has had for Leinster in a while," said forwards coach Jono Gibbes.
By the time Healy left the field, he had pounded out the first try, been part of the maul for the second and made the third with a shuttle pass from off the floor.
This is not to ignore the heavy carrying and hard hitting that typifies his game married to much improved scrummaging strength.
Gibbes cited Van der Merwe as "a real soldier" in the trench warfare that is the natural environment for a loose-head prop.
This evolved out of the less eye-catching news that Van der Merwe is possibly a target for French clubs, just like Ireland's out-half Jonathan Sexton.
"Heinke has been immense for us. He's consistent. He is physically a real soldier. He has been a great asset, very rarely injured or unavailable. A real worker. Any team wants guys like that," said Gibbes.
Doubtless, Leinster will need 15-23 soldiers to wage war on the Exeter Chiefs and storm Sandy Park.
Gibbes continued the party line: "We've got a massive job on our hands. We're playing a really good, combative, well-organised team. Exeter at home have got a serious backbone.
"I think our preparation is realistic in what we're facing. We've got to be focused on physically getting a foothold in that game first and being really clinical in understanding what we are up against."
While Sean O'Brien was right to indicate they won't be going down the same road as Clermont Auvergne, they know that four tries are possible because of the French club.
"Exeter have been broken down once for four tries at home by those guys in yellow," said Gibbes.
The boys in blue must do the same.