text: Deila's side visit Romania's Astra Giurgiu on Thursday knowing a win, coupled with a Salzburg victory over Dinamo Zagreb, will seal qualification.
  "I am happy with the position," said Deila.
  "If we win tomorrow we have a very good chance of going through and it would be the biggest achievement of my career."
  The Celtic manager led Stromsgodset to the Norwegian top-flight league title in 2013, but says progressing in the Europa League would be a more significant achievement.
  "It will be very big. We are talking about Europe now," added the 39-year-old.
  "It is hard to compare achievements but there are more teams in the tournament and it is much bigger to go through in Europe than be a champion in Norway."
  Celtic beat the Romanians 2-1 in Glasgow two weeks ago with Stefan Scepovic and Stefan Johansen bagging the goals to leave their side on seven points.
  In-form striker John Guidetti is ineligible for the Europa League group stages and with Anthony Stokes ill, Deila is expecting Scepovic to step up after netting his first goal for the club against Astra.
  "Of course we want to have every player available but we are lucky at Celtic that we have a very big squad," the Norwegian said.
  "It is a big chance for him (Scepovic) to show his quality.
  "We really believe we can win but we know it's going to be a tough game. We had a tough game at Celtic Park and away it's going to be even more difficult. We need to keep on improving as we have in the last month and hopefully we get three points."
  Guidetti, who will be available if Celtic progress from Group D into the knockout phase, has said the club can win the Europa League, but Deila is not looking that far ahead.
  "There's a lot of matches to come before we can think about that and the level is very high in Europe," he said.
  Skipper Scott Brown is also expecting a real test against the Romanians.
  "It was hard at Celtic Park a couple of weeks ago and we are expecting the same again," he said.
  "It surprised us when they came to Celtic Park and were comfortable on the ball but we got the result we were looking for."
  Meanwhile, Brown revealed the Celtic players are standing by Bulgarian winger Aleksandar Tonev.
  The Celtic player, who is in the squad for the Astra match, has been hit with a seven-game domestic ban for racially abusing Aberdeen's Shay Logan, but the Scottish champions have appealed the decision.
  "We all stick by him," added Brown. "We know he didn't say it so that's the main thing and all the lads in the dressing room believe him."
target: Celtic boss Ronny Deila reckons reaching the last 32 of the Europa League would mark his finest moment as a manager.