The Hoops got an early scare when an effort from just outside the box cannoned off Craig Gordon’s left hand post.
Real Sociedad were a well-drilled outfit and Celtic, in their all-green change strip, struggled to make headway.
However, on the positive side, Deila’s men looked a lot better organised than the team that was too easily taken apart in Dukla Prague’s 5-3 win at the same venue last weekend. Israeli international midfield Nir Biton’s presence certainly helped bring some composure to the line-up.
Just after the half-hour mark, another new Bhoy, Dedryck Boyata, almost broke the deadlock when he flashed a header over the bar after a fine corner-kick from Stefan Johansen.
Darnell Fisher came on for Mikael Lustig at right-back for the start of the second-half.
Five minutes later, the SPFL champions were out of luck when Leigh Griffiths robbed a Spanish defender on the edge of the box and drilled a shot against the woodwork.
On the hour mark, Van Dijk replaced Bitton with Mulgrew stepping into midfield before Ciftci was given a great reception as he replaced Griffiths at the centre of the attack.
The Turk didn’t take long to make his mark as he earned a free-kick then pushed a pass into the path of former Tannadice team-mate Mackay-Steven who fired a low drive into the net from 20 yards..
Ciftci was put through one-on-one a few minutes later, but the Sociedad keeper made an excellent stop from his shot.
Celtic pushed for a second and Swiss defender Saidy Janko also made his debut when he replaced Mackay-Steven with 15 minutes to play.
Overall, Deila will know his side still have some way to go, but, on this performance against a La Liga side, they showed they should have too much for their Icelandic challengers in Glasgow in midweek.
And Celtic’s new signing can sleep well known that he’s now a full fledged Bhoy, having had his photo taken with Paul the Tim!
PS Nice little stadium, pity we don’t have one like that of our own as a second home for the Bhoys, young Bhoys & the Celtic Ghirls…
Starting line-up: Gordon; Lustig, Boyata, Mulgrew, Izaguirre; Brown, Bitton; Armstrong, Johansen, Mackay-Steven; Griffiths. Subs: Fasan, Fisher, Forrest, Rogic, Henderson, Ciftci, Van Dijk, Ambrose, Tierney, Stokes, Scepovic, Janko.