Another booking; this time full back Seamus Coleman has his name taken for obstructing the rampaging Andrew Robertson.

Gordon Strachan, on the touchline, puts both hands up, Zumba class-style, pleading for a free kick. It's a tight, scrappy affair. Can either side fashion a piece of brilliance to break the deadlock?

What a save! Aiden McGeady thinks he'll be celebrating a goal on his return to Celtic Park but, with low shot appearing destined for the bottom corner, David Marshall gets an oven-gloved mitt out to push the ball away.

Steven Fletcher trots off to be replaced by Chris Martin as Scotland boss Gordon Strachan shuffles his pack. We've got a little over half an hour remaining at Celtic Park.

Roy Keane, usually aflame on the touchline with eyes like burning orbs, is calmness personified in the visitors' dugout.

Image source, Getty Images

Colin Brown: "@BBCSportScot @BBCRadioScot Hope Scotland can sneak it, but both teams lack a real class player."

Scotland goalkeeper David Marshall, like a grizzly bear securing a leaping salmon, grabs the subsequent corner with ease. It remains goalless but the game is beginning to come to the boil again...

Five minutes into the second half and the visitors are pinging the ball about the pitch with aplomb. Suddenly, they quicken the pace and Aiden McGeady fizzes in a dangerous corner and the Scotland defence do just enough to thwart Jon Walters. Corner for the Republic of Ireland.

BBC Sportsound pundit Willie Miller

"The Irish will be happy that it's a physical game but we're not; we want to get the ball down and play."

Everton right back Seamus Coleman is seeing a lot of the ball in the opening minutes of the second half as the Republic of Ireland force a number of throw ins as they inch their way deep into Scottish territory.

Colin Simpkins from Livingston: "It's about time Steven Fletcher was dropped in favour of Jordan Rhodes, 1 goal in 20 odd matches is pathetic. What is Gordon Strachan thinking about?"

We're back under way. Goals please and plenty of them...

It's very, very tight at Celtic Park.

AndyBear: "#bbcscotfootball no skill from either team - all kick & rush only excitement so far has been the bad tackles."

Bruce from Dundee: "Only Gibraltar vs Germany on the box here in Mexico. Surely Alan Gilzeans "last" hat-trick for Scotland record will go when they visit Hampden? Germany 3 up, going on 10."

Frustration for supporters late to arrive and filter through the turnstiles at Celtic Park. Gnashing of teeth, too, for both sides as they've come within a whisker of breaking the deadlock. At the break, it remains goalless and the slice of orange will taste bitter sweet.

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Two minutes of added time at the end of an absorbing and fiercely-contested first half...

"That [Fletcher chance] should've been taken. The ball should be in the back of the net," laments BBC Sportsound pundit Willie Miller.

Scotland manager Gordon Strachan trots back to his seat in the dugout and commits his thoughts to paper; he's scribbling away furiously.

What a chance! Shaun Maloney brilliantly takes a long through ball out of the night sky with a Karate Kid-style jump and control before sliding a delicious low cross into the area. However, the on-rushing Steven Fletcher can't apply the finishing touch. Groans rain down from the stands. That could, and perhaps should, have been the opening goal.

Shane Long can count himself a lucky boy. The Rep of Ireland striker fells Grant Hanley with an eye-watering challenge but no booking from the whistler from Serbia.

James McClean slaloms past a couple of Scotland challenges but the Wigan winger can't get a decent delivery into the box as a nervous hush envelopes the home supporters.