Both sides showed plenty of endeavour and the early exchanges were vigorously contested, but penalties and a lack of ball control didn't allow either side to control territory. The first scoring opportunity wasn't made until the tenth minute when a loose clearance gave Leinster scrum half Luke McGrath a long range drop goal attempt which went wide.
The visitors were getting an increasingly healthy supply of ball and one move lead to a kick through which resulted in a scrum 5. The Blues were not about to give up a try that easily and scrum half Adam Meads hassled the Leinster back row causing turnover ball that was quickly moved downfield, winger Matthew Roberts being stopped short, but a penalty allowed the visitors to clear.
Leinster were still creating opportunities, luckily for the Blues full back Ross Jones put his three penalty attempts wide, and when the referee blew for half time neither side were on the board.
The second half started a little brighter with both sides having been presumably lectured about controlling the ball at half time. The visitors had the early pressure, but solid defence saw no points forthcoming. When the Blues did have the ball they created their best chance of the game. A sweeping move by the back saw winger Rees bundled into touch 10 metres short. At the line out though Leinster conceded a penalty that Lewis Williams landed for the first points of the game.
The game then became littered with handling errors, much of the second half was played between the two 10 metre lines, there was little indication of the drama that unfolded in the last few minutes.
First Leinster scored a well-worked try in the corner that looked like being the match winner. From lineout ball the moved the ball through the hands, full back Jones appearing in the line to create an overlap for winger Mark Roche to score, the conversion crucially though went wide.
From the restart the Blues gained a penalty just inside their own half, Lewis Williams stepped up to attempt to win the game but missed the kick. From the 22 drop out the ball went deep into the Blues half. With time nearly up there was no option other than to move the ball through the hands, they reached the visitors 22 and at the ruck a penalty for hands was awarded. Williams eyed up the posts and this time he didn't miss.
Cardiff Blues had won a game they didn't look like winning until late in the second half, but the know they will have to play better than this if the want to win their next Championship game against North Wales on the 27th.