CALLUM McGREGOR confessed Celtic were caught cold by Salzburg as the Austrians stung their hosts twice early on to inflict a 3-1 defeat on Ronny Deila's side.

Two goals in the first 13 minutes from Alan stunned Parkhead into silence as the Europa League Group D leaders threatened to run amok in Glasgow.

Despite Red Bull's early blitz and the eventual result, Deila's Bhoys still progressed into the competition's last 32 after rivals Dinamo Zagreb were sunk 1-0 by FC Astra in Romania.

But reflecting on the game, admits the SPFL Premiership champions were 'shocked' by a quickfire start they failed to rectify.

The winger said: "We knew that they liked to press high and get after us, but it shocked us a wee bit that they were coming here and having a real go.

"After the two goals we kind of gathered ourselves and really pushed on. We definitely deserved a draw.

"If the result in Romania hadn't gone our way it would have gone to the last game. That would have put the pressure on.

"But thankfully Astra have done us a favour. It's a relief, but we're delighted."

While Deila threw on Kris Commons, James Forrest and Aleksandar Tonev midway through the second half in Glasgow, McGregor told how tabs were being kept on the game being played 2000 miles away.

"When I came off, a couple of the boys behind the dug-out were keeping us informed with the score in Romania," said the 21-year-old.

"We found out with a couple of minutes to go that they were 1-0 up and it was looking good for us.

"We were still focused on the game, but to hear a bit of news like that while we were getting beaten was positive.

"The result is a bit of a dampener, but we're through and that's what everyone wants.

"We wanted to progress and get European football and we've done that."

Despite letting three goals in, if it wasn't for the brilliance of Craig Gordon it could have been even worse for Celtic. The Scotland international pulled off a stunning save to deny Martin Hinteregger from point-blank range.

But rather than focus on the negative, Gordon preferred to join McGregor in looking at the positives.

He said: "It's a

disappointing result, but the second half was a lot better. The game could have gone either way.

"I'm disappointed we didn't do it by ourselves, but we did enough in other games to get through and that was the main objective, so job done."