Llanelli were on the receiving end of a hammering in France for the second successive week as they plunged to the bottom of Pool A.
After last week's defeat at the hands of Stade Francais, this latest setback meant the Scarlets had conceded 97 points in two trips across the Channel.
The Welsh side took the lead with a penalty by Daniel Rogers after 18 minutes and they held on until a try by former French international scrum-half Guy Accoceberry was converted by Pascal Fauthoux 15 minutes later.
But Llanelli had their gameplan blown apart when they were ravaged by injuries in the first halfhour of the match.
Three Llanelli backs - Nigel Davies, Stephen Jones and Wayne Proctor - were all forced off and in positional terms only scrum-half Rupert Moon and left-wing Garan Evans finished the half where they had started it.
Begles forced home their advantage with six tries in the second half with two going to captain Olivier Brouzet, the French international second row. Lucas Martin (two), Christophe Dongien and Francis Ntamack claimed the others.
Llanelli break-aways were all too scarce, although they did have two chances to score tries when they trailed 31-3 midway through the second half.
But second row replacement Tony Copsey was held up as he went for the line and a three-quarter move ended with a pass to another replacement, Aled Thomas, spilling the ball.
Llanelli's only consolation was a try after 79 minutes when replacement flanker Ian Boobyer went over after good work by Chris Wyatt.
Racing Club hooker Fabrice Landrau was given a 30-day suspension yesterday after being sent off in his club's 31-20 European Shield defeat by Caerphilly.