Former Celtic goalkeeper Pat Bonnar on BBC Radio Scotland

"There is lots and lots of space on Celtic's right-hand side but they have not got in one single cross. Callum McGregor has been playing far too narrow. I wouldn't be surprised if James Forrest is brought on."

Over in Romania, it's 0-0 between FC Astra Giurgiu and Dinamo Zagreb. If the results stay the same, Celtic are going through.

BBC Scotland's Richard Wilson at Celtic Park

"For half an hour, Celtic were lost souls. They were overwhelmed by the swift incisiveness of Salzburg, whose strikers were mobile and dangerous. The 2-0 lead did not flatter the visitors, but Celtic recovers, scoring once and renewing belief. This game is not, yet, out of Celtic's reach, but they need to be more commanding in midfield and more sure-footed at the back."

Rab McKnight on BBC Sport Scotland's Facebook, external page: "After a few minutes, commentator said Celtic defending with everyone in around the box... I was ready to switch off right there - before the first goal. Celtic have done this in every European game for the last 5 years. It can ONLY put pressure on the defence. Who, exactly, are you going to clear the ball to? The opposition evrry time. It's bad enough late in the game but starting like that, what can you hope for? 0-0? Unfortunately we don't seem to play until we go behind. So frustrating. "

Steve Burnsey: "Delia might get away with it AGAIN tonight but his day is coming soon."

Thomas Clark: "I think they will get possibly a draw but you never know, long way to go yet and scottish football needs an interest in the new year in Europe."

Celtic are not really taking advantage of Salzburg losing their stride as they struggle to retain possession. It's all very scrappy now as Efe Ambrose makes an important tackle to prevent Alan from running in on goal.

Salzburg's Benno Schmitz is booked for clattering into Callum McGregor near the halfway line. The Austrians have lost their earlier fluency as the interval approaches.

HarryBanty on Twitter: "So much for all the talk about Soriano. There is an Alan!#bbcscotfootball"

Andy Craig on Twitter: "#bbcscotfootball Deila no clue how to manage Celtic. 2 best players on the bench & playing defensive at home. Go now Ronny it didn't work out."

BBC Scotland's Richard Wilson at Celtic Park

"Celtic's goal has completely changed the mood at Celtic Park. The home crowd has been roused and the home team is playing with more purpose. Also telling that the breakthrough came with Emilio Izaguirre's first real foray down the left flank. Celtic can profit from their wide play."

Stefan Johansen is cautioned for a trip and not even his best 'who me?' innocent face can save him.

More from BBC Scotland's Facebook, external page (all before Celtic got that goal back...)

Kenny Matthews: "Shocking. Will he never learn? Commons benched again."

Iain McGowan: "Maybe Deila should have been arrested rather than Craig Whyte?

Completely out of the blue, Celtic are right back in it as Emilio Izaguirre sends a dipping cross into the penalty area for Stefan Johansen to meet first-time near the penalty spot and the Norwegian's shot flies into the bottom corner of the net.

Another swift counter-attack from one penalty box to the other and again it's the Austrians treating us to some lovely interplay. Alan, may have a boring name by Brazilian standards, but he is full of clever invention.

BBC Scotland's Richard Wilson at Celtic Park

"Ronny Delia has been grim-faced on the touchline. His Celtic team is being outplayed, particular in midfield, where Salzburg have taken control. The home side's wide players have barley participated, but Salzburg adopt a narrow formation, which Celtic could take advantage of. First, though, the Celtic defenders need to curtail Alan and Jonathan Soriano, because the Salzburg strikers have been irrepressible so far."

It's all flicks and tricks from a super-confident Salzburg, with the Celtic defence creaking. Alan plays a lovely pass to Soriano but Virgil van Dijk manages to force the striker wide and it's a comfortable save for Craig Gordon.

Jonathan Soriano raises his arm in celebration as his free-kick arcs round the defensive wall and flies into the net. However, referee Halis Ozkahya also raises his arm to indicate the set-piece was indirect. I think Craig Gordon knew that as he let the ball whizz by...

Steve Burnsey on Facebook: , external"Said it for the last 2 months Delia his not good enough to manage a pub team... Raging."

BBC Scotland's Richard Wilson at Celtic Park

"Salzburg look threatening every time they attack. Celtic need to tighten up. The home fans had been in good voice before the opening goal, but the Austrian side are accomplished and sharp."

Oh dear. Celtic are all at sea as Alan helps himself to a second goal. The ball is nodded on from a corner by Andre Ramalho and, again, the Brazilian is left unattended to poke the ball past Craig Gordon.

A second goal for Salzburg surely? The ball loops to Martin Hinteregger almost underneath the crossbar with Celtic in complete disarray but Craig Gordon produces an incredible save to keep out the header.

Were the Celtic defence waiting for an offside decision? There was no challenge on Alan at all.