RONNY DEILA admits his maiden season as Celtic boss has been a mixture of 'hell and heaven'.

The Norwegian has had a rollercoaster campaign at Parkhead since replacing Neil Lennon last summer but has achieved his main objective and lead the Hoops to their fourth successive Premiership crown.

While Celtic have been impressive in recent months, Deila got off to a shaky start at Parkhead as his side were eliminated from Europe by Maribor after a controversial Champions League tie with Legia Warsaw.

After seeing the Treble slip through their fingers after they were beaten by Inverness Caley Thistle in the Scottish Cup semi-finals, the Hoops will end the campaign with the Premiership crown and League Cup to their name.

Deila takes his side to Pittodrie this weekend as they look to finish with a flourish this term and the boss has enjoyed his first taste of Scottish football.

"It has been an unbelievably good experience for me," he said.

"It has been tough at times and very happy at times and that's why you love football.

"It is hell or heaven and you have to be used to it and you have to love having sh**** times and to turn it around and be happy because it is never something in between.

"It is always very good or very bad.

"(The hell times) is easy to answer.

"The first six month was very tough. The Champions League (qualifying) campaign was very hard.

"I didn't feel so much a part of it but I had to manage it.

"That was the tough part of course, as well as the beginning of the season when we struggled in the league.

"We lost 15 points (before New Year) and we lost five after that and that's what makes me happy.

"The Europa League is not talked about so much but it was a big thing to get through the group stages and play European football in winter.

"The two games against Inter Milan were some of the highlights of the season and we deserved more in those two games.

"Things are improving and I am eager to take it forward to the next stage."

Celtic will start the new season as firm favourites to make it five-in-a-row and add more domestic silverware to their tally but it is in Europe where the biggest tests will lie next term.

And the former Stromsgodset boss is confident his side will be better placed to reach the lucrative Champions League group stages at the second time of asking.

Deila said: "We are in a totally different situation than the one we were in last year.

"The most important thing is keeping players. We need consistency and the players here are good enough to take us into the Champions League.

"But we need to make the squad stronger and make it more competitive."

With the end of the season in sight, Deila will soon be able to delve into the transfer market once again and look to bolster his squad for another Euro bid.

The Parkhead boss will lose defender Jason Denayer when he returns to Man City at the end of his loan spell while the future of centre-back partner Virgil van Dijk is also uncertain.

The Dutchman is not short of suitors in England and abroad and Deila insists Celtic can still bring out the best in him.

He said: "Denayer goes back to Man City and we have to look at what we do there, that is a challenge.

"But there is more in it for us to get into the Champions League than to sell Virgil van Dijk.

"Virgil also needs a good Champions League campaign and if we get into the group stages he will get the challenges he is after.

"He is a very good player but still we can make him better.

"He should go to the biggest clubs in the league, not the small clubs in the biggest leagues with money."