Barça created 17 chances against Juve but only one was on target as they were held to a goalless draw, exiting the Champions League 3-0 on aggregate.
Roberto said: “We created a lot of chances but nothing would go in, if it had, we would have been in the tie.
“We leave disappointed. We have to be critical and look at the mistakes and approach the end of the season in the best possible fashion. We still have the league and the Copa del Rey and every game will be decisive."