BBC Sport's Jonathan Sutherland: "Huge crowds still not inside 15 mins after kick-off. Fans not happy."

Aiden McGeady - being booed with every touch since kick-off - earns himself even more abuse as he clatters Steven Fletcher and goes into the book. Both sides will be lucky to end the game with 11 men at this rate! It's being played at the tempo of an Old Firm game...

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Northern Ireland looking well drilled and organised. So far, so good.

Former Scotland international Pat Nevin on BBC Radio 5 live

"There is many a referee that might have given a red card."

Grant Hanley, you are a lucky boy! A bad touch from Hanley is pounced on by the nuisance Shane Long, Long toes it clear and Hanley just hacks him down! He's a long way from goal - just inside the Scotland half - but nobody would have caught him.

Referee Milorad Mazic shows a yellow card to a relieved Hanley. Scotland could be down to 10...

Alan in Glasgow: Wish the Tartan Army would forget the booing and get behind the team like usual. Come on Scotland.

The floodgates have opened - Thomas Muller puts the world champions ahead. Could be a long night...

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Scotland link play together neatly on the edge of the box as first Shaun Maloney and then Steven Naismith threaten to get into the area, but John O'Shea steps across to block Naismith off brilliantly. Scotland settling into the game now, with the Republic looking to use that pace up front.

Our match stats tell me that Gibraltar have had 7% of the possession so far. SEVEN.

What was that, kick-off? Still goalless though...

Former Scotland international Pat Nevin on BBC Radio 5 live

"Left-back Andrew Robertson has just arrived on the scene, but in these early exchanges he has got the better of Aiden McGeady."

Steady start in Bucharest - which I will no doubt call Budapest at least once this evening, apologies in advance - as the table-toppers Northern Ireland look to control in midfield.

There is the tempo, noise and feel of a big Celtic game in the Champions League already. The place is rocking as left-back Andrew Robertson delivers a wicked cross to the near post but John O'Shea does brilliantly to clear his lines. Fabulous ball in.

Open start at Celtic Park. Scotland threaten next, with Steven Fletcher rising unmarked to meet a swirling right-wing corner, but the Sunderland man leans back and heads over the top.

Ex-NI defender John O'Neill on BBC Radio Ulster

"What an atmosphere, in many ways it resembles the night we had against Wales in the Millennium Stadium a few years ago. It's not full here, but it is some noise.

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"Northern Ireland deserve to be top of the group, but I think we're all agreed this will be the hardest game so far. I just hope the players realise they are top of the group on merit and keep passing the ball and playing as we have done throughout the campaign."

Scotland concede a cheap free-kick inside 45 seconds, Jon Walters flattened by a blue shirt. James McClean takes the dead ball but skims it poorly into the wall.

Walters then fires in a low shot which is well held by David Marshall. Fine start from the visitors in white.

And we are under way in Romania and Glasgow too...

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Under way in Nuremberg where Gibraltar have kept a clean sheet so far...

Former Scotland international Pat Nevin on BBC Radio 5 live

"Scotland can't afford anything else but a win - a draw at a push. Scotland have one or two weaknesses - Grant Hanley and Russell Martin are not blessed with great pace in central defence."

Anthem time. The teams emerge to what is very nearly the theme from 'Top Gun' before a passionate rendition of both anthems. In a European qualifying campaign which has been flat at times, this is a proper international game. Bagpipes and all...

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The teams are out at Bucharest - where the roof of the impressive stadium is closed this evening. Can Northern Ireland keep their fine campaign on track?