London Wasps take on Newport Gwent Dragons at Rodney Parade on Friday night targeting home advantage in April's quarter-finals - but rocked by news of the departure at the end of the season of Billy Vunipola.
Wasps, who beat the Dragons 38-25 in Round 1, have qualified as Pool 3 winners with 21 safely banked. Bath Rugby head the hunt for to ranking on 24 points followed by Gloucester Rugby on 22.
No 8 Vunipola has made three tournament appearances for Wasps, scoring a try against the Dragons, but will join Saracens from next season.
"We are clearly hugely disappointed," said Wasps Director of Rugby Dai Young.
"Billy is a player that the club identified some time ago as one with huge potential and he's been developed by London Wasps, despite a period when he struggled with illness and injury, into one of the brightest young talents in English rugby.
"Although we are bitterly disappointed right now, it is only fair for me to say that I believe that Billy will become a top quality international player for years to come and we wish him the best with his career.
"There is a long way to go in the season and I am sure he will give his all for Wasps in the coming months."