Rangers have won the Scottish Championship title and have gained automatic promotion to the Scottish Premiership.
Deila has suggested that he has been impressed with the performance of the Gers so far this campaign.
However, the Norwegian has made it clear that Celtic are ready for the return of their Glasgow rivals to the top flight of Scottish football.
“Rangers have shown they are the best team in the Championship and of course we are ready to take them on next year,” Deila told The Scottish Sun.
“They are a big club and when they are good enough, that’s a positive thing,” added the Norwegian.
Rangers and Celtic are fierce Old Firm rivals, and the two teams playing in the Scottish Premiership is only going to be good for Scottish football.
The Gers have a strong team, but they will have to invest in one or two top-quality players in order to compete with the Bhoys for the league title next season.
The two Glasgow giants will face each other later this month, when they take on each other in the semi-finals of the Scottish Cup at Hampden Park in Glasgow.