Wales centre Jamie Roberts enjoyed a happy Harlequins debut on Saturday, scoring one of seven second-half tries in a 59-7 trouncing of Calvisano in the European Rugby Challenge Cup.

Roberts suffered a dead leg last week when he represented Cambridge University in the Varsity match against Oxford.

However, in his first outing for Harlequins - now all but assured of a quarter-final place having claimed 20 points from four Pool Three matches - the 29-year-old was able to play his part in a dominant win as the visitors to The Stoop crumbled after trailing 14-7 at the interval.

Nine Harlequins players crossed, with Ben Botica kicking seven conversions in addition to his touchdown.

The Dragons retained top spot in Pool Two courtesy of a 34-17 bonus-point victory over Pau, who remain winless despite a spirited second-half showing in which they scored all of their points.

Earlier in the day, Sale Sharks had briefly moved ahead of the Dragons by beating Castres 31-10, all three of the Premiership club's tries coming after the break.

Zebre moved up to second in Pool Four with an impressive 25-5 triumph over La Rochelle at Stadio Sergio Lanfranchi.

La Rochelle ran out 27-19 winners in last week's reverse fixture between the sides, but were well beaten on this occasion as Zebre recorded a second win from as many home matches in the competition.

Brive also made the most of playing on home soil, bouncing back from last week's shock 10-7 defeat at Enisei-STM with a 33-3 bonus-point win over their Russian Pool One rivals.