Racing racked up their biggest win in the tournament while also inflicting Scarlets’ heaviest defeat in Europe.
Ex-Munster man Casey Laulala scored a hat-trick as the French Top 14 leaders ran in nine tries at Stade Yves-du-Manoir.
Laulala crossed twice while Juan Imhoff, Bernard Le Roux, Louis Dupichot also touched down in the first half that also saw Scarlets briefly reduced to 13 men.
Scarlets reduced the damage on the scoreboard with tries from DTH van der Merwe and Gareth Davies early in the second half. But Imhoff claimed his second after the pack secured a penalty try and Johan Goosen and Laulala completed the rout late on.
Dupichot made the most of opposite number Van der Merwe’s yellow card when he raced clear to clinch the bonus point that Racing needed to secure a home tie in the quarter-finals. Laulala then stepped through a tiring Scarlets defence on the stroke of half-time for a staggering 38-0 lead at half-time.
Van der Merwe grabbed his first European try for Scarlets after the break. Former Wales scrum-half Phillips was sin-binned as Scarlets pressed and his successor Davies made the most of the space from the back of a scrum to grab a second try after 50 minutes.
However the Racing pack combined with a driving maul that earned a penalty try. Imhoff was in support to take a scoring pass for his second try that took Racing past 50 points. Laulala completed his hat-trick two minutes from time to take Racing past 60 points for the first time in Europe.
B Dulin; L Dupichot, C Laulala, D Carter, J Imhoff, R Tales, M Phillips; E Ben Arous, D Szarzewski (capt), B Tameifuna; L Charteris, M Carizza; Y Nyanga, B Le Roux, A Claassen
M Collins; S Evans, R King, H Parkes, DTH van der Merwe; S Shingler, G Davies; P John, K Owens (capt), S Lee; T Price, M Paulino; R Pitman, A Shingler, M Allen