London (AFP) - Ireland's Six Nations Grand Slam will give an added pep to Munster and Leinster as the Irish provincial powerhouses bid to reach the last four of the European Champions Cup this weekend.
Both are at home with two-time champions Munster, having lost just once as hosts in the quarter-finals, welcoming French giants Toulon, who won the trophy three years in a row from 2013 to 2015.
Three-time champions Leinster have the highest profile quarter-final as they host two-time defending champions Saracens in a sold-out Lansdowne Road on Sunday with the English side praying that England fly-half Owen Farrell will be fit.
Farrell will be seeking his own redemption having been outplayed by Leinster's playmaker Johnny Sexton in the Six Nations clash at Twickenham.
The other two quarter-finals feature Wales's Scarlets hosting French side La Rochelle on Friday and an all-French affair as French champions Clermont, reeling from a 49-0 whipping by Toulon last weekend, welcome Racing 92 on Sunday.
The last few weeks have been incident-packed for Munster skipper Peter O'Mahony.
Having played a prominent role in the Grand Slam success, he proposed to his long-time girlfriend -- and got the response he wished for.
However, history is never far from Irish minds and O'Mahony is no different in recalling the one quarter-final Munster did lose at their Thomond Park fortress, to Ulster in April 2012.
"Unfortunately the bad memories are always the ones that stick out, and you always have a little bit of fear driving you on," he said.
"That's part of being an elderly fella who has played a few times in the knockout stages and been beaten. You don?t want to be back there again."
O'Mahony pinpointed the resurgent France centre Mathieu Bastareaud as a serious threat and a huge obstacle to Munster progressing -- a hurdle which will grow even bigger if Munster's star backs Simon Zebo and Andrew Conway fail to win their repsective fitness battles.
- 'Against the world' -
Sexton for his part is not using the Six Nations triumph as a weather vane in terms of ending Saracens' run as kings of Europe -- indeed the English side secured a memorable semi-final win over O'Mahony's Munster at Lansdowne Road last year.
Sexton described that performance as "brilliant" this week and added the English club seemed to thrive off "that 'against the world' (vibe)".
"Look there are a few leftover players (from the England match, a 24-15 victory for the Irish on March 17) that are playing for Saracens and there are a few playing for us but I think it is totally different circumstances," said Sexton.
"They are back-to-back champions and we are sort of striving to get back to where we were and become that champion team ourselves."
Farrell will be key to Saracens' hopes -- they are giving him until Friday to prove he has recovered from a quad injury -- but extraordinarily robust centre Brad Barritt will take the field.
Only on Tuesday he had a plate inserted under local anaesthetic into his fractured cheekbone and refused having a general anaesthetic as it would have ruled him out of Sunday's clash.
"It was much like a routine tooth operation!" the 31-year-old told the club website.
"Thankfully it's not something that will rule me out of the weekend.
"It's not a game I want to miss and in terms of the preparation we've had with the full session (on Wednesday) I'm confident with it."
Clermont's season revolves round beating Racing 92 as there is little chance of them defending their domestic title -- they are ninth 16 points off the top six play-off places with just four matches to play.
"We're playing for our season, we know it," said Clermont captain Morgan Parra.
"Either you're still alive (after Sunday) or the season stops there and it will be, excuse the expression, shitty."