PETER Lawwell, the Celtic chief executive, yesterday defended Ronny Deila, who has been subjected to growing criticism as a result of his side’s disappointing performances in Europe this season, and confirmed he will be given time to prove himself.

However, Lawwell also stressed the Parkhead club had to start performing better in continental competition - and expressed hope the Scottish champions would win their last two Europa League group games and progress for the knockout rounds.

Deila faced calls for his removal from many disgruntled Celtic supporters after his team lost to Malmo in the Champions League play-off in August and failed to qualify for the lucrative group stages for the second season running.

Successive defeats to Molde, who are currently languishing in sixth place in the Norwegian league, in the Europa League since that disappointment have increased the pressure on the former Stromsgodset manager.

Celtic can, despite their losses to Molde, still progress to the last 32 of the Europa League if they win their last two Group A matches against Ajax at home next Thursday and Fenerbahce away a fortnight later.

In an interview shown to shareholders at the Celtic AGM yesterday, Lawwell admitted the Glasgow club had “underachieved” in Europe this season and needed to show a stark improvement in the future.

“Clearly this season we have started and we have struggled in Europe which is bitterly disappointing and has hurt everybody at the club – nobody more than Ronny and the players,” said Lawwell.

“It has been a real challenge for us and we have to do better, we must do better. That is the aim for everyone at the club. We have to perform at the highest standard.

“We are still in Europe. We are still in the Europa League at the moment. Hopefully we can get out of our group. But we must improve and nobody knows that more than Ronny and the football staff.

“At home we have recovered. We are at the top of the league and are in the other two competitions and we have the opportunity to go for the Treble.

“So far we have to be honest and say that in Europe we have underachieved. But I think domestically we have reasserted our dominance and hopefully we will go and take the Treble this year.”

Lawwell praised the work Deila, who was a surprise appointment when he succeeded Neil Lennon as manager last summer, had done with his players since arriving in Scotland and there would be no “knee-jerk” reaction to bad results in Europe.

“He is a young manager,” he said. “We hired him on the basis of a lot of fundamental qualities he has got. He is a developer, he is a builder, he is a creator of players and teams. And that takes time. I don’t think you can have a knee-jerk reaction to something that has happened over two or three games.

“We tend to look after our people here at Celtic and we look after the manager in particular and we give them time to progress. You can see the results in the league and the cups last year and the position we are in domestically this year you can see there has been an improvement in our players.

“Virgil last year improved, Jason Denayer improved under Ronny, Nir Bitton unquestionably has improved, Leigh Griffiths and of course we are now seeing young Keiran Tierney coming through.

“These are products of Ronny’s development and coaching. That is what we need to do. We need more of that and I’m sure we’ll get more of that in the coming years.”