The Celtic boss has been discussing his forward after the 1-0 win over Motherwell.
Three points took the Bhoys back to the summit of the Scottish Premiership table and it was the 23-year-old who scored the only goal of the game.
And Deila feels Ciftci has been improving of late, with this start, goal and performance something to build on for the Hoops forward.
RD on Nadir Ciftci: "He has been improving. He got a start today and got the goal that gave us 3 points, good for him to build on." (MH)— Celtic Football Club (@celticfc) October 17, 2015
Despite his goal, some fans have suggested Ciftci didn't do enough for Celtic overall. But, as Deila says, the 23-year-old can build on his performance and duly deliver from hereon in at Parkhead.
HITC Sport recently suggested the forward could be Celtic's most important player in the coming weeks and he proved that against Motherwell.
Celtic can't keep relying on Leigh Griffiths and, if Ciftci can up his game, the Bhoys will have a far greater chance of competing both domestically and in Europe week in week out.
Deila's side travel to Molde in the Europa League next Thursday, where it will be interesting to see what side the Norwegian picks.