Barcelona midfielder Oriol Romeu says defeat at Shakhtar Donetsk must be a wake-up call.

Barca lost 1-0 to leave their Champions League round 16 hopes in the balance.

Romeu said, "Hard defeat. We wanted to certify the qualification. It could not be. We have to improve and give less options to the rival. We have to find solutions because it is costing us.

"A hard game. They close well back and it costs us since the ball did not roll well. They were able to score in the first half and it has given them wings. It is hard, but it's time to get up.

"Every defeat is a warning. We have to be self-critical and see what we have done wrong to correct it quickly."