Celtic manager Ronny Deila has stressed that his side must continue to improve following their slender 1-0 victory over Dinamo Zagreb in the Europa League.

The Hoops were left hanging on against their Croatian opponents at Celtic Park this evening following an early goal from Kris Commons.

Craig Gordon needed to produce a fine display to thwart the attacking threat of Zagreb in the second half, with Deila admitting that the performance left him feeling angry.

"I think they were better in the second half but we started well and had a fantastic goal," the 39-year-old told reporters. "The first half was good, and in the end it was fantastic team spirit. We have to take that with us but we need better passing.

"It is important for us to test ourselves against good teams but we need to have longer periods like the first half. I am happy to win but there is anger inside me to play better. Our players worked so hard and we will continue developing. We have a good chance of getting the 10 points I think we will need."

Celtic currently lead the way in Group D with four points from their opening two games in the competition.