|European Challenge Cup, Pool Three|
|Harlequins (28) 34|
|Tries: Buchanan, Clifford, Yarde, Chisholm Cons: Evans 4 Pens: Evans, Botica|
|Cardiff (0) 26|
|Tries: Allen, Fish 2, Williams Con: Patchell 3|
A second-half Cardiff Blues revival was not enough to stop Harlequins winning an entertaining European Challenge Cup pool match that featured eight tries.
Rob Buchanan, Jack Clifford, Marland Yarde and Ross Chisholm all touched down as Quins took a commanding 28-0 lead into half-time at The Stoop.
The Blues responded with two tries from Dan Fish and scores from Cory Allen and Lloyd Williams to make it 31-26.
However, Ben Botica's late penalty ended hopes of a remarkable comeback.
Victory means Harlequins are guaranteed a home quarter-final in April after five bonus-point wins from five games.
Cardiff will likely need a bonus-point win of their own at home to bottom-of-the-table and pointless Calvisano in their final pool match on Friday to keep their quarter-final hopes alive.
Harlequins took just four minutes to open the scoring with hooker Buchanan crossing from close range.
New England call-up Clifford then shot over from a maul 15 metres out and winger Yarde finished off another close-range attack.
After Mike Brown dropped the ball over the Blues line, Chisholm ran onto a kick through to seal the bonus point before half-time.
Jamie Roberts was the only Welshman enjoying himself at that stage with a series of trademark charges to cross the gain-line regularly.
But Allen barged his way over under the posts just three minutes after the break and Rhys Patchell converted before Fish got the visitors' second try shortly afterwards.
Williams shot through for a solo effort from 20 metres out and Fish's second try put the Blues within range as Patchell kicked the conversions.
But Quins finally roused themselves and Botica's penalty with the last kick deprived the Welsh side of a second point.
It was a generally positive afternoon for Eddie Jones' six England squad selections, with Chris Robshaw named man of the match.
The exception was Joe Marler, who went off clutching his chest and looking groggy a minute after the break.
Wales' utility back Gareth Anscombe made his first appearance since the World Cup, just two days before their Six Nations squad announcement.
He played the final 25 minutes at fly-half with Patchell moving to full-back.
Harlequins director of rugby Conor O'Shea said:
"They play really good rugby, the Blues, and we knew if they had the ball, they'd cause us trouble.
"We had most of it in the first half, we knew we'd cause them trouble. We scored some good tries and fortunately held on."
On the performances of his England squad players:
"I thought Mike Brown played really well, his usual feisty self and counter-attacked well.
"Danny Care was sharp and they're all in good form and feeling confident. Joe Marler's fine, just a jarred joint."
Cardiff Blues head coach Danny Wilson said:
"I think the first 20 minutes just shell-shocked us, but second half we played a certain shape and structure.
"Until that last scrum, we were in a position to come away with two bonus points.
"Missing that second bonus point may make (the quarter-final) a step too far for us, but we need to get another win at home (against Calvisano)."
Harlequins: Mike Brown; Marland Yarde, George Lowe, Jamie Roberts, Ross Chisholm; Nick Evans, Danny Care (capt); Joe Marler, Rob Buchanan, Will Collier, George Merrick, Charlie Matthews, Chris Robshaw, Jack Clifford, Nick Easter.
Replacements: Joe Gray, Mark Lambert, Kyle Sinckler, Mat Luamanu, Luke Wallace, Karl Dickson, Ben Botica, Charlie Walker.
Cardiff Blues: Dan Fish, Blaine Scully, Cory Allen, Ray Lee-Lo, Alex Cuthbert, Tom James; Tom Patchell, Lloyd Williams; Sam Hobbs, Kristian Dacey, Taufa'ao Filise, Macauley Cook, James Down, Josh Turnbull, Ellis Jenkins, Manoa Vosawai.
Replacements: Ethan Lewis, Tom Davies, Dillon Lewis, Lou Reed, Cam Dolan, Tavis Knoyle, Gareth Anscombe, Gavin Evans.
Referee: Andrew Brace (Ireland)
Touch judges: Mark Patton (Ireland), Jonathan Peak (Ireland)
TMO: Jude Quinn (Ireland)
Citing commissioner: Yann Le Dore (France)