The Bhoys boss has seen great strides from two key members of his squad this term.
During a campaign in which the Bhoys claimed a domestic double, including their fourth consecutive Scottish Premiership title, Deila has singled the duo out for the strides they have made since the beginning of the season.
Indeed, slow starter Bitton has become a key member of Celtic's midfield, while Griffiths - whose Hoops career also began slowly - is now the Scottish champions' top scorer.
And, in a Twitter Q & A session with the club's fans, Deila showed no hesitation in singling the duo out.
Meanwhile, the Celtic boss was also asked about goalkeeper Craig Gordon, who was nominated for the club's Player of the Year award but missed out to Stefan Johansen.
The experienced shot stopper had been out of football for some time through injury but moved to Parkhead on a free transfer last summer. The rest is history.
Deila's response is telling, of course, as Celtic will need Gordon to be exactly that - European class - in order to make it through to the Champions League group stages (and possibly beyond) next season.