Both Rogic's and Forrest's careers have been plagued by injury so far, with the duo finding it difficult to stay out of the physio room.
As a result, the Bhoys have had to give the duo individual training schedules, and Deila believes that these methods have helped get the best out of both men.
"Tom's form is nothing to do now being lucky with injury, rather that we are taking the fitness of every player really seriously and we do everything we can so they train to avoid injuries," he said.
"You need consistency in training. You need to look after them if they have been out for a long time with injury. You can't allow them to train every day because they will get injured again.
"So we have built up Tom. This is why he has been playing well and he had a really good game on Sunday. It is the same with James Forrest. Now you can see him doing much better because he is fit. This is just the start. We have to keep them motivated, disciplined and we will get consistency from them."
Rogic's form for Celtic this season has seen him become one of their breakthrough stars, after what has been a difficult period for the midfielder at Parkhead to date.
The Australia international joined the Bhoys in 2013, but prior to this season he has failed to hold down a regular place in their line-up.
However, since the opening of the campaign, Rogic has made seven appearances, and after scoring three times, he seems to have become a key part of Deila's plans.
Forrest, meanwhile, has made most of his appearances as an impact substitute this term, but he will be hoping to play a more prominent role as the season progresses.