Cardiff Blues director of rugby Mark Hammett says his players must improve their decision making after falling to their third Pro12 loss of the season.
It had looked as though Blues would come away with a losing bonus point at Leinster on Friday but went down 37-23.
The Welsh side opted to go for an equalising try and turned the ball over and instead it was Leinster who scored.
"The smart choice would have been to kick the ball out and take a point away," Hammett said.
"We got ourselves back in the game and pretty well back in the game.
"We knew we'd have to be right on our best against Leinster. They play a pretty wide game, a lot of behind balls and a lot of times we shut it down.
"But unfortunately at times we didn't always get our reads right and there's also some individuals who have to look hard at themselves around making their tackles."
After winning their opening Pro12 game at Zebre, Blues have fallen to defeats at the hands of Glasgow, Ulster and now Leinster.
Hammett, who took over Blues this season, is happy with the effort being put in by his players but says that hard work will only carry them so far.
"Now we need to add the finesse and add some of the shape to it," Hammett added.
"Once again we were an improvement but it always hurts when you see 37 points against your name... it was nice to score two tries but that first half we should have got over the line at least another two or three times."
Blues travel to Connacht on 3 October and then face Welsh rivals Ospreys away on 12 October.
Meanwhile, Blues will face Rovigo in the European Rugby Challenge Cup group stage this season after the Italians sealed their place with a two-legged play-off win 46-39 on aggregate over Tbilisi Caucasians, a combined side drawn from Georgian clubs.
Rovigo are best known in Wales for the late Carwyn James's coaching spell there between 1977 and 1980, while the Ospreys have cultivated links in recent years.
French side Grenoble and London Irish of the English Premiership are the other two sides in Pool 1.