|Cardiff Blues (7) 24|
|Tries: Smith, L Williams, Dacey Cons: Anscombe (3)Pen: Anscombe|
|London Irish (7) 14|
|Tries: Cross, penalty try Cons: Geraghty (2)|
Cardiff Blues earned a third successive Challenge Cup win after dominating the second-half against London Irish.
Lloyd Williams scored the decisive try for Blues on 63 minutes as he finished off the game's best move, started by Cory Allen and Richard Smith.
Kristian Dacey's score made the result secure before the Exiles were awarded a late penalty try.
A lacklustre first half saw the teams tied at 7-7 with Geoff Cross's charge-down score cancelled out by Smith.
The Welsh region welcomed back Alex Cuthbert, Cory Allen and Gethin Jenkins from Wales international duty while fit-again Matthew Rees returned to reclaim the captaincy.
Irish brought in former Scarlet Andy Fenby, Eoin Griffin and Topsy Ojo to reinvigorate their backline after the disappointing 21-9 loss against Gloucester.
But neither side could find any rhythm in a disjointed first half in which their league struggles were all too evident.
Irish struck after eight minutes when Gareth Anscombe saw his kick charged down by Scotland prop Cross, who charged 20 metres to score with Shane Geraghty converting.
But Anscombe held his nerve to create the Blues' response three minutes later with a deft chip that was gathered and powerfully finished off by wing Smith.
Anscombe added the conversion but that was the extent of the scoring before the interval, with both kickers missing two penalties each.
Both sides struggled to find any continuity, with Irish failing to make their extra man advantage count when Blues captain Rees was sin-binned.
After the break it was the visitors' turn to be reduced to 14 men as flanker Jebb Sinclair saw yellow.
Anscombe slotted over a penalty, but the Blues failed to take any further advantage as Lions prop Jenkins was held up over the line and the Irish defence kept out a series of close-range scrums and line-outs.
Sinclair's charge as the game entered its final quarter brought a rare breakout from the visitors.
Then the home side produced a moment of quality on 63 minutes as Smith and Allen combined from their own 10 metre line and Williams finished it off.
The Blues made sure of the victory five minutes from time when replacement hooker Dacey crossed from close range, with Anscombe again adding the extras.
London Irish had the last word when a penalty try was awarded against Cardiff for collapsing the scrum, but although Geraghty drop-kicked the conversion there was no time to restart.
The result takes the Blues four points clear of the Exiles before next week's meeting at the Madejski Stadium.
Cardiff Blues: Adam Thomas, Alex Cuthbert, Cory Allen, Gavin Evans, Richard Smith, Gareth Anscombe, Lloyd Williams; Gethin Jenkins, Matthew Rees (captain), Adam Jones, Filo Paulo, Josh Turnbull, Macauley Cook, Ellis Jenkins, Josh Navidi
Replacements: Kristian Dacey, Sam Hobbs, Craig Mitchell, Rory Watts-Jones, Manoa Vosawai, Lewis Jones, Gareth Davies, Dan Fish
London Irish: Fenby; Lewington, Griffin, Geraghty (capt), Ojo; Noakes, Steele; Court, Paice, Cross; Cox, Low; Sinclair, Cowan, Treviranus
Replacements: Palframan, Harris, Halavatau, Leo, Narraway, Allinson, Sheridan, Homer
Referee: Alexandre Ruiz (FFR)
Assistant Referees: Laurent Cardona and Arnaud Blondel(both FFR)
TMO: Herve Dubes(FFR)