The Reds held a 1-0 advantage ahead of the return match at Anfield, but that was cancelled out when goalkeeper Jose Reina let a David Templeton shot squeeze through after 85 minutes.
"We knew it was going to be tough," he said on ESPN. "We made more hard work of it than we should have done.
"We were a little bit wasteful in front of goal.
"However, the manager stressed to the team 'don't go down under pressure', and I think we bounced back well.
"We created lots of chances we didn't finish though and we have to be more clinical in front of goal. That was a lesson for us."