Ospreys' backs coach Gruff Rees was very disappointed with his side's performance in the 21-13 LV= Cup defeat to Cardiff Blues at the Liberty Stadium.
"The Blues did a good job on us in terms of a game they might not have deserved to win," he said.
"But that's down to our own ineptitude. There is a huge amount of learning we have to do from not taking line break opportunities.
"We suffered a total of 20 turnovers which is a huge stat in itself and the Blues just capitalised on that. They put points on the board when they had their opportunities. You could argue we conceded two soft tries.
"There was plenty of endeavour in our game and we tried to open it up but we gave up some cheap field positions.
"But there were some young players out there and they will learn from a game like this."
Cardiff Blues fly-half Simon Humberstone was delighted with his winning display in his first start for the region.
The 26-year-old, who plays semi-professional rugby for Pontypridd, kicked 11 points including two penalties, a conversion and a drop goal.
"It was a massive opportunity," Humberstone said. "We brought a young side down here and it was a chance for a lot of players.
"We knew there was an opportunity to get a big 'W' on the board. We probably weren't as clinical as we could have been but there's lots of stuff to go back and work on ahead of Munster next week."