Jiten Chandarana: GB finally made a return of JMDP's serve down the line on set point. Mayer has been crossing every time...

Miles Maclagan
Former British Davis Cup player on Radio 5 live sports extra

A courageous effort from the British pair, they hung around, lost a bit of momentum in that second set but never let it slip away.

A Leonardo Mayer block volley floats long to open up 15-30. 

Great Britain are just two points away.

Make that one as Juan Martin del Potro's lob strays over the back for 30-40.

First serve missed by Delpo.

Jamie Murray reads Mayer's gamble and plugs his return down the line for an easy winner as the net man heads in the opposite direction to try and cut him off at the pass.

Great Britain take a topsy-turvy and potentially decisive third set.

There is a bit of bounce in the Murray boys' heels now.

They get out of a 30-30 hole with Andy Murray lucking out on the final shot, scraping an unintentional drop-volley over via the frame of his racquet from a bazooka forehand from Juan Martin del Potro.

Argentina, and Juan Martin del Potro specifically, serve to stay in the third set next.

Andy Murray throws his head back and roars as Argentina bury a shot into the gauze.

Feeling a little fatigued? A jumbo shot of adrenaline right to the heart.

Leonardo Mayer wobbles to 0-30 and belief courses around the gangways of the Emirates Arena.

An over-cooked forehand long by Mayer flies long and the Murray clan have 15-40 and two chances of an immediate break-back.

Juan Martin del Potro hammers away an overhead off an attempted lob return to save the first.

Argentine come out on top to save the second in a rat-a-tat exchange at the net.

Here comes a third though.

John Lloyd
Former GB Davis Cup captain on BBC One

Del Potro’s expression never changes, a bit like Bjorn Borg used to be. It’s a bit unnerving. Without the injuries he definitely would have won a few more Grand Slams.

Andy Murray plays with fire as he serves right into the Juan Martin del Potro hitting zone at 15-30 down.

Maybe that just caught the big man by surprise. His eyes spun round to cherries and he tugged his shot long as he tried to max out the power on return.

Thirty-all.

Jamie Murray into the net on volley. Break point Argentina.

A Jamie volley creeps over the net after walking the wire for an agonising fraction of a second. One saved.

Here comes a second though.

Andy misses with his first serve.

And Del Potro picks off his second with a sublime backhand guided down the line!

Groans around the Emirates Arena as Andy Murray cracks a backhand cross-court into the top of the net with Great Britain 0-15 to the good.

Andy dollies up a simple slap-down for Leonardo Mayer on the next point as well. 30-15.

Judgement of Solomon from Jamie Murray as he reins in his reflexes, leaves a Leonardo Mayer volley and is rewarded by the sight of it dropping long over the baseline behind him for 40-30.

Juan Martin del Potro's disguised dig down the line proves too canny though and the Argentines are over the border and safe once more.

Image source, Reuters

Andy Murray with an almost exaggerated soft-hands volley keeps the ball at the very limits of Leonardo Mayer's stretch.

Jamie Murray pummels the resulting pick-up away for a clean winner.

A hold with a bit of space to spare.

Leonardo Mayer is staring down the barrel of 15-40 and two break points.

He dredges two big serves up from the depths though and keeps the Murrays from the door.

Plenty of Argentine decibels as the blue shirted duo complete their escape.

The spotlight spins round to Jamie Murray, the next to try and limbo his serve under the return radar.

Image source, reuters

John Lloyd
Former GB Davis Cup captain on BBC One

That was a crucial game and to me Andy Murray looks jaded out there. It looks like this a real fight for him just to get going, he’s a bit slow on the return of serve. Jamie has played so well today and needs to keep up this level. We thought it was going to be easy the way they started this match but not now.

It feels like we are getting to the crux of this match.

Jamie Murray's serve survives an thorough examination. Both pairs are coming under pressure on serve.

Who will crack first? Where is the weak link?

Great Britain captain Leon Smith is training his motivational patter on Andy Murray at the changeover. 

Image source, Getty Images

The Juan Martin del Potro serve comes under siege.

But if any shot is capable of blasting its way out of a corner...

The big man saves a first break point with a kicking tee-off that Andy Murray is annoyed at not being able to return and a second is salvaged with one ripped past Murray's backhand.

Leonardo Mayer finally snuffs out the danger with a pouncing volley at the net that hits Jamie Murray's shoulder rather than strings.

More like it from the Murray brothers who open with a statement-of-intent love hold.

The British fans indulge in a bit of call and response chanting during the swap of ends.

There is something still surprising about the quality partisan atmosphere after years of Great Britain languishing in the bottom reaches of the Davis Cup.

It is like stumbling on a pop-up drum and bass gig in the aisles of M&S.

The Juan Martin del Potro serve creaks to 15-30 and there is fresh energy in the urging from the home stands.

The Tower of Tandil - and what a nickname that is - is made of stern stuff though.

A dismissive swat of a forehand brings up 40-30 and a crackerjack serve means that we are level pegs.

Great Britain keep their cards on the table, just.

Juan Martin del Potro forces deuce with a lovely deft redirect return that divebombs an advancing Jamie Murray's toes.

Another superb return - this time from Leonardo Mayer  - also proves too good for a stooping Jamie and forces break and set point.

Great Britain knock it back. And a second.

Some lovely net-play cut and thrust in this game.

John Bercow - backing the Brits over the top of his smart shirt again - is locked onto the action.

Finally the Murray brothers get over the line.

Argentina to serve for the set next.

The Argentina pair were warned about their lengthy pre-point tactical chats by Pascal Maria during a previous changeover and now the umpire issues them with a code violation for taking too long.

Juan Martin del Potro raises a quizzical eyebrow, but it is Leonardo Mayer who looks like his dander is really up.

He crashes across court and then down the line for successive winners right out of the centre of the strings. 

Image source, Reuters

Andy Murray's serve is back online.

Those volleys though...

Britain's number one touch at the net lacks purpose and bite and two limp volleys are punished by the Argentine pair to turn 40-15 to deuce.

Jamie Murray shows his younger brother how it is done, walloping hard into tight angles and away for winners.

Speaker of the House John Bercow is in the tennis house again today after being spotted in the stands yesterday. 

Image source, Reuters