Ange Postecoglou has switched Stephen Welsh to the left of defence and Carl Starfelt to the right after the pair were exposed at times in recent games.

However, it doesn't seem to have made any difference to Celtic's leaky back line.

James McFadden
Former Scotland forward on BBC Sportsound

How did that stay out?

AZ are testing Celtic with their pace and are through on goal again.

This time it is new signing Vangelis Pavlidis who breaks through and the striker's low drive is Joe Hart's toe away from scoring as his shot comes off the inside of the post and into the grateful goalkeeper's arms.

Zakaria Aboukhlal goes down after speeding into the Celtic penalty box and looks pleadingly at the referee, who waves play on.

Nervous moment for Celtic - and fortunate to get away with it.

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

AZ show their intent as they win the first corner before the clock has reached one minute.

Celtic survive that and a nervous moment as a clearance from goalkeeper Joe Hart is almost intercepted right in front of goal.

The Celtic huddle is over, the referee's whistle rings out and AZ kick-off in their all-red strip, Celtic in their traditional green and white hoops, but who are making their usual progress to the group stage?

We'll be a bit closer to the answer in 90 minutes time...

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

The noise levels are cranking up and the hairs on the back of neck beginning to stand as Celtic Park roars out "You'll Never Walk Alone"...

Probably the most interesting fact about AZ head coach Pascal Jansen is that he was born in London to a mother who once had the lead role in the English version of Hair.

Indeed, after she moved to Amsterdam with musician hubbie Hans when Pascal was a nipper, Sue Chaloner teamed up with one Iwan Groeneveld in a duo called Spooky And Sue.

A kind of Dutch answer to Ike and Tina Turner, they reached number two in their domestic charts with their version of the Bing Crosby classic, "Swinging on a Star", in 1974.

However, when they looked to reach Eurovision '76 with follow-up "Do You Dig It?" through their National Song Contest, the public didn't - and they sadly finished last. Celtic fans will be hoping her son's foray into Europe gets the football equivalent of nil point.

"We want to get on top of the tie early," Celtic manager Ange Postecoglou tells BBC Scotland's Sportsound.

"Particularly at home in front of a capacity crowd, we want to get people on their feet nice and early and get an energy behind us that makes us difficult to stop."

On Liel Abada's return to the line-up, Postecoglou says: "He's had a great start to the season.

"It's probably the one area, that front third, where we've got the opportunity to rest someone.

"I'm hoping, with his energy, speed, pace, he can put some pressure on them."

Image source, SNS

AZ head coach Pascal Jansen was left reeling by that opening competitive league defeat at the weekend to Waalwijk.

"I was shocked by our performance against Waalwijk as I did not recognise my team from our preparations," he said. "I didn't see that coming, but we've moved on, the focus is entirely on Celtic and some things will be different.

"Celtic have a new coach and they have started to play nice football, which is great in such a short period of time. Besides, 50,000 people in the stands certainly influences the atmosphere. We are looking forward to it."

AZ captain Teun Koopmeiners has been linked with Atalanta and Rennes and was on the bench for the weekend defeat by Waalwijk but returns to their midfield in one of three changes.

Norway midfielder Fredrik Midtsjo also comes in, with Vangelis Pavlidis, the Greece striker bought from Willem II this summer, making his first start.

Netherlands international Jordy Clasie and fellow midfielder Tijjani Reijnders drop out along with Sweden striker Jesper Karlsson.

Peter Vindahl Jensen, the 23-year-old goalkeeper signed from Danish Superliga side Nordsjaelland, is on the bench, with Hobie Verhulst making just his fourth appearance since joining AZ from Go Ahead Eagles last year.

There's also famous name on the bench - Maxim Gullit, the 20-year-old defender son of former Chelsea and Netherlands striker Ruud.

Image source, PA Media

There was disappointment already tonight for Celtic, with their women's side losing out to Levante in Champions League qualifying.

Fran Alonso's side, making their European debut, were always the underdogs but gave the side who finished third last season in Spain a fright.

Can Ange Postecoglou's side go one better?

Former Motherwell and Dundee United goalkeeper Sieb Dijkstra, who recently left his coaching role at Eredivise club Fortuna Sittard, thinks Celtic can cash in on AZ's summer upheaval.

"AZ are a club in transition," the Dutchman told BBC Scotland. "A lot of key players left this summer - you saw on Sunday how badly they were missed - and the only significant signing is striker Vangelis Pavlidis from Willem II.

"Celtic have a really good chance to win this tie because AZ are not the team they were last season.

"The main dangers for Celtic will be Pavlidis, who was prolific for Willem II, Koopmeiners - if he starts - and Dani de Wit, a talented midfielder who can score goals."

Image source, SNS

Former Scotland and Hearts manager Craig Levein has been impressed with Celtic's forward play since the arrival of Japan striker Kyogo Furuhashi but remains concerned about their defence's vulnerability to the counter-attack.

"If there is any question mark over any area of Celtic's team, it will be found out in these two matches and this AZ team will be technically good I'm sure and will test them," he said.

"Even on Sunday, when they dominated the match completely, Josh Ginelly comes on for Hearts with his pace and caused them problems down that side as Carl Starfelt was exposed and had no cover.

"The way they play, with the two full-backs pushing high, as a centre-back you need to be able to run in that Celtic team because you get exposed and that exposure of the defence allows what happens in front to be exciting because they overload the midfield area with those two full-backs."

Image source, SNS