Cardiff Blues made a near perfect start at the RDS on Saturday but they were overhauled by a fast-finishing Leinster side who had full-back Luke Fitzgerald to thank for topping off their sixth straight league win.
The Blues, who welcomed back Robin Sowden Taylor, Tom James and Jamie Roberts from international duty, made a blistering start to this top-of-the-table clash.
Sitting five points behind Leinster before kick-off, Dai Young’s men knew a big win would draw them level with the league’s top side as the title race gathers pace.
Both sides fielded strong line-ups despite the enforced absence of some Six Nations stars and it was Leinster, captained for the night by lock Leo Cullen, who were caught napping in the early stages.
After Luke Fitzgerald had found touch close to the halfway line, Cardiff secured lineout possession and set about picking and driving their way towards the hosts’ 22.
It was a strong showing from the Blues forwards and they made it all the way to the try line with flanker Maama Molitika stretching over one-handed for a fourth-minute score.
Full-back Ben Blair stepped up to add the conversion and he also turned Nick Macleod’s 11th-minute try into a seven-pointer.
The Blues played some lovely off-the-cuff stuff to work Macleod over for one of their tries of the season.
Jamie Robinson was the one to break Leinster’s defensive line initially and with Sowden Taylor and Jason Spice keeping the move flowing, Macleod sliced through on an excellent diagonal run to score to the left of the posts.
14-0 down, Leinster were in serious trouble but once they cut out the errors, the home side began to click with fit-again winger Shane Horgan, Keith Gleeson and stand-in hooker Ollie Le Roux throwing their weight around.
As so often is the case, Argentinian star Felipe Contepomi lit the touch paper for Leinster’s comeback.
After a ruck infringement by Xavier Rush and a brief dust-up between Spice and Contepomi, he knocked a 20th-minute penalty through the posts.
Despite the best efforts of Macleod and Gareth Thomas, Leinster grew in confidence as the half wore on and after a mammoth 21 successive phases, during which Cian Healy, Christian Warner and Le Roux all went close, centre Michael Berne popped up on the left wing for a morale-boosting try.
Eight minutes before the break, Leinster looked to have run out of space as a powerful Blues defence kept them in check but when Horgan swung a pass out to the left, Berne was able to step past Spice and cross the whitewash.
Contepomi’s successful conversion attempt cut the gap to four points but Blair replied for the visitors – notching the second of two late penalty opportunities – to hand his side a 17-10 lead to take into the second half.
The Blues made some costly errors during the early part of the second half and when Molitika was found infringing at a ruck, referee Peter Allan lost his patience and sent the try-scoring flanker to the sin-bin.
A few minutes earlier Contepomi had landed his second successful penalty and his third followed after Cardiff went down to 14 men.
All that meant the Blues’ advantage was suddenly down to 17-16 and despite some brilliant touch finders from Tom James, Leinster kept the pressure on the visitors.
Just past the hour mark, Contepomi kicked Leinster into the lead for the first time.
Thomas and Jamie Robinson helped get the Blues back within range, close to the home 22, with some midfield thrusts and one such attack gave Blair a much-needed sight of the posts.
The New Zealander was off target with the lengthy penalty attempt and Macleod also missed to the right when he attempted a drop goal.
With the clock running down, it took a moment of magic from the Ireland-capped Fitzgerald to settle the tie.
The young Dubliner took the ball on out on the left, kicking past his opposite number Blair and winning the foot race to get his left hand to the ball before it rolled out over the end line.
Contepomi missed the conversion to the left but his kick was not needed as Leinster hung for what could prove to be a vital win in their push for a long-awaited second league title. The victory also sealed Leinster’s first ever season’s double over Cardiff – they were 30-19 winners at the Arms Park in November.