Liverpool boss Brendan Rodgers says his players defended poorly from set-pieces during their narrow defeat against Basel.
The Reds did well to earn a hard-fought win in their first game of the group but the September 16 win against Ludogorets Razgrad continues to be their last as they struggled for form over the last few weeks.
And there is more room for concern for Rodgers after a defensive mistake gave Basel the win on Wednesday night.
"We didn't start great and I don't think we were very good technically tonight, certainly for the first 25 minutes," Rodgers told Sky Sports 5.
"Once we started to combine and pass the ball we created some very good openings. I think we had enough chances to at least get something from the game.
"I think it [set-piece defending] is something we continue to talk about and look at and analyse but you have to deal with it on the field and the key to defending is your first contact with the ball and we continually don't do that enough.
"But we defended very, very poorly on the corner and it's not the first time so it's very, very disappointing we couldn't get something from the game and the game was decided by a poor defensive corner.
"The boy [Mario Balotelli] is trying, he is working hard."
