Celtic eased past Stjarnan in their Champions League second qualifier - but not before an early scare against the Icelandic part-timers.
The Hoops travelled to the tiny Samsungvollur stadium with a 2-0 advantage from last week's first leg in Glasgow but found themselves under some unexpected pressure after only six minutes when Olafur Karl Finsen shot the home side into a shock lead.
However, midfielder Nir Bitton eased the nerves when he levelled in the 32nd minute from a Stefan Johansen corner and when defender Charlie Mulgrew fired in a second early in the second-half it was all over as a contest with late goals from substitute Leigh Griffiths and Johansen making it 4-1 to see the Hoops through 6-1 on aggregate.
Ronny Deila's side will play Qarabag in the third qualifier, with the first game at Celtic Park next week, and are sure to be tested to a greater degree against the Azerbaijan outfit who came through their tie against Montenegro's Rudar Pljevlja.
Deila said: "It's difficult to say what the performance was but when you play on an artificial pitch that's dry, it's sticky and everything goes slow.
"We were sloppy and a bit stressed but we got the goal and more tempo.
"In the second half there was only one team on the pitch.
"There's no problem to play artificial but when you don't water a pitch it's totally different.
"We always ask for a pitch to be watered but they said it was broken."
On his side's poor start, the Hoops chief added: "We didn't want to concede an early goal but it happens sometimes in football and you need to bounce back. But 4-1 is a positive result and I'm looking forward to the next match."
With seven minutes on the clock, the hosts shocked Celtic by making the breakthrough. Following a swift breakaway down the left, Jeppe Hansen picked out Finsen, who cut inside and fired calmly beyond Craig Gordon.
Eventually, the home side's resistance was broken from yet another Celtic corner, Bitton rising highest to bullet home a header.
The Scottish champions only took four minutes of the second half to complete the turnaround, Mulgrew finding the net. Griffiths and Johansen completed the scoring.
Dundalk saw their campaign come to an end as they were held to a goalless draw at home by BATE Borisov, who advanced 2-1 on aggregate.
Welsh champions The New Saints took Videoton to extra time in Hungary but eventually went out 2-1 on aggregate after a 1-1 draw on the night.