The Celtic boss was 'very impressed' with the 19-year-old on Wednesday night.
Deila chose a strong Celtic side to face their lower-league opponents in the Scottish League Cup - clearly wary of the possibility of a cup upset that would be disastrous so early in the Hoops' season.
That's doubly so considering the fact the Bhoys won this tournament last time around.
Janko, meanwhile, was one of those to ensure Celtic didn't slip up - and his Norwegian manager heaped praise on the 'quick, strong and young' defender who he feels has plenty of potential.
RD on Man of the Match, Saidy Janko: I was very impressed with him. He’s so quick and strong and young, and he has a lot of potential.— Celtic Football Club (@celticfc) September 23, 2015
RD: Individually a lot of players did well & the attitude was good the whole match. We'll face whoever we get & we want to win the Cup again— Celtic Football Club (@celticfc) September 23, 2015
Next up for Celtic is a Scottish Premiership clash with Hearts this Saturday afternoon, in a competition where Deila's men are currently five points behind league-leaders Aberdeen.
There's plenty to compete for on all fronts, then, during a busy period in the Bhoys' campaign - and performances like Janko's will certainly come in handy for Deila and co.
Celtic fans will no doubt hope the 19-year-old will stay loyal when his potential leads to being noticed by other clubs. For now, though, the Hoops can enjoy watching him develop as an exciting player.