Celtic beat Hearts 2-1 to book their place in the League Cup semi-final.
The Bhoys beat Hearts 2-1 in the League Cup on Wednesday to secure their progress to the semi-final stage of the competition.
And Deila was delighted with the way that Johansen and Bitton acquitted themselves, after Celtic lost Scott Brown to injury just before kick-off.
“Their performance makes it even better after losing our captain but we have a good central midfield.
“There’s an Israel national team player and a Norwegian national team player there so we have good subs coming into those positions. Those two played very well.”
Biton and Johansen have been two of the players to benefit most from Deila’s leadership at Parkhead.
The duo have improved considerably since the Norwegian boss took charge, and they both now play very important roles for the side.
It is, therefore, no surprise that they stood out against Hearts, and they will be hoping to form a strong partnership over the coming weeks, if Brown’s injury turns out to be a serious one.
Brown remains an important player for Celtic, due to his all-action approach, but Deila clearly feels confident that he has the players to cope without his captain.