John Lloyd
Former GB Davis Cup captain on BBC Two

We were one point from Del Potro serving from the set and that is not a guarantee but it would be a great shape for him to be up 2-0.

It is about these small margins but that is what great players do, come up with these shots.

Mid-noughties indie disco staple The Fratellis get a little bit of airplay dough as Chelsea Dagger is dusted off in the changeover.

Murray to try and break for the set next.

Andy Murray is staring down the barrel at break point down.

A few whispered words to himself as he stands on the service oche.

A crackerjack serve wide, a scamper in behind and a forehand volley punched down the sliver of unguarded court.

Break point saved.

Reflexes sharpened to a fine point, as he slam dunks away Del Potro's scoop up in the front court to seal the game and a narrow escape.

Every point now is leaden with significance, heavy with import.

Andy Murray shuts down the angles to lure Juan Martin del Potro into the net for 15-15.

His backhand down the line has been jippy though. Another is gobbled up by the gauze to give Juan Martin del Potro 15-30.

An ace out wide 30-30 and a modicum of relief to the British fans.

Murray punches down the line on his backhand. This time it stays on the leash. Del Potro can't claw it back. 40-30.

The Argentine harpoons another mammoth forehand away for a winner though. Deuce.

Image source, Reuters

Juan Martin del Potro is a man who the Emirates Arena seems to shrink around.

Six-foot-six-inches of Argentine means the slices of open court on his side are few and skinny.

Andy Murray harumphs loundly as he buries a backhand into the net after getting a quick glimpse.

The Scot is pressing into the net more and more, but he is not picking his approaches very wisely. Del Potro is slapping winners past him with ease.

Image source, Getty Images

John Lloyd
Former GB Davis Cup captain on BBC Two

That was an excellent service game from Murray.

I think we will see an aggressive game here from him on the return of serve.

He is taking a few more chances and I think he has got to. He has to get Del Potro out of his pattern.

And he isn't.

Andy Murray produces an impeccable service game to hold to love.

He seems to be revving up for the home straight of this second set. And he has the scoreboard lead which might tug at any tension in the Del Potro serving arm.

Image source, PA

John Inverdale
BBC commentator in Glasgow

This is a big moment. Andy Murray cannot afford to get broken here.

Andy Murray sleepwalks into the net like a lemming on the opening two points of the game.

There are some pointed looks between him and captain Leon Smith. It looks like a pre-determined tactic is not working for them.

A superb stretching swat across court from the Scot brings up 30-15, but Murray strays long twice more to allow Del Potro through without undue exertion.

Image source, PA

John Lloyd
Former GB Davis Cup captain on BBC Two

If this was a normal tournament Murray would be in trouble but, in this circumstance, he hears the crowd and sees his teammates and it is just a different thing than anything a player is involved in, 

You squeeze out that extra bit of energy and fight.

Andy Murray, with skidding angles and a shrewd raid to the net, holds to love.

We are getting to the pointy end of this second set fast.

Andy Murray cannot afford any mistakes now. Two sets to love down means a very long and scenic route is the only way to victory.

When officials get involved in sport, it rarely ends well for them.

Umpire Pascal Maria spills a stretching one-hander from the high chair.

Better leave it to the ball boys and girls.

He calls "game Argentina" as Del Potro holds to 30.

This is a lot more straightforward than the tussles and traumas of the first set.

Andy Murray now rattles through his own service game to love.

By the way, Great Britain have met Argentina in four previous Davis Cup matches, winning just one way back in 1928.

Image source, Reuters

Not the start Great Britain were hoping for, click play below to see Juan Martin del Potro secure the first set with an ace.

Juan Martin del Potro's serve is chugging like a steam train.

A production line of bruising tee-offs as he holds to love.

He is looking serene at the moment.

Image source, Reuters

John Lloyd
Former GB Davis Cup captain on BBC Two

Murray's serve got him out of trouble there.

Without his first serve on a few important points he would be even further down.

Del Potro has been flawless so far.