Deila attended the Scottish Championship game between Rangers and Falkirk at the Falkirk Stadium last Friday evening.
The Bhoys will face their Old Firm rivals in the semi-finals of the Scottish Cup at Hampden Park in Glasgow next month.
Celtic boss Deila has suggested that he could continue to watch the Gers in action live in order to prepare for the tie in April.
“I might watch them again,” the Norwegian told The Glasgow Evening Times. “There is nothing new in that. We watch teams all the time before we play them, so it is nothing out of the ordinary.
“I saw their game against Falkirk up until it was 2-2 so I got a good impression of the match but we will see what is going to happen over the next few weeks."
Rangers were expected to win the Scottish Championship game against Falkirk, but they suffered a 3-2 defeat.
Mark Warburton’s side took the lead as early as the seventh minute when Kenny Miller found the target.
The Glasgow giants went 2-0 up just two minutes later through Barrie McKay, and it appeared as though the Gers were going to win by a very big margin.
However, Rangers collapsed in the final 20 minutes of the game to lose 3-2, as Blair Alston, Myles Hippolyte and Bob McHugh found the target for the home side.