The Bhoys looked devoid of ideas for large parts, although they eventually made the breakthrough on 73 minutes when Stefan Scepovic headed home a cross at the back post.
It was not to be for Astra, however, with the home side holding out for all three points which sees them remain top of the group.
See how the game unfolded with Sports Mole's live text coverage below.
CELTIC STARTING XI: Gordon, Lustig, van Dijk, Denayer, Izaguirre, Brown, Mulgrew, McGregor, Johansen, Stokes, Scepovic
ASTRA GIURGIU STARTING XI: Lung, Youseff, Morais, Oros, Pliatsikas, Yahaya, Seto, Enache, Laban, William Amorim, Budescu
CELTIC SUBSTITUTES: Zaluska, Ambrose, Matthews, Tonev, Griffiths, Kayal, Wakaso
ASTRA GIURGIU SUBSTITUTES: Coman, Gaman, Florescu, Chitu, Rus, Bukari, Fatai