Chelsea ace Eden Hazard says they'll need to play on the front foot in Barcelona for the second-leg of their Champions League round 16 tie.

Lionel Messi's 75th-minute strike at Stamford Bridge on Tuesday night ensured Barcelona walked away from their round of 16 first leg tie against Chelsea with a crucial away goal.

Willian had opened the scoring for the hosts with his fine, curling effort earlier in the second half.

"At least we won't be able to think defensively in the second leg because if we think defensively over there we will be in a lot of danger," said Hazard.

"We will go there trying to win because we have to score and we will try for the perfect game as we did today except for the small error that we made. That's what made the difference because you're up against Barcelona.

"Against other teams, perhaps you get away without letting in a goal. We played well. We had a plan to defend well, Perhaps we could have done more with the ball when we had it. It's not over. We can still dream. Qualification is still possible."