Neither side could realistically qualify for the semi-finals but the Blues put on an impressive display, running in five tries in front of nearly 6,000 fans.
Harlequins enjoyed a sustain period of pressure after a cagey first 15 minutes but failed to make it count as a resolute Blues defence held firm on its own try line.
The Blues found some territory of their own and immediately made it count, Lewis Jones going down the blind side from a scrum before releasing Filo Paulo to power over from close range.
Paulo’s try came against the run of play but the Blues capitalised on their lead straight away. Gavin Evans made the most of Quins poor handling on their own line to extend the home side’s lead.
A shell-shocked Harlequins side replied with a try of their own on the stroke of half time, the ball was spread wide to full back Ollie Lindsay-Hague in space and he went over to take Quins into the break 14-5 down.
Any hint of a comeback was quashed just two minutes into the second half when a lovely Blues move saw Tom Williams break the line and put it on a plate for Dan Fish to run in from the 22.
The Blues secured the bonus point five minutes later when Owen Williams’ interception allowed the Blues to break. Quick ball allowed Macauley Cook to pick and go and send full back Tom Williams over to put the game out of sight.
The last half hour was subdued, illuminated only by a first glimpse of Samoan international Isaia Tuifua. The home side rounded off their victory three minutes from time with a try for hooker Marc Breeze, Simon Humberstone making it five out of five conversions to give the Blues a 35-5 win.
