Special Davis Cup afternoon in Glasgow for Andy and Jamie Murray

The local heroes defeated Juan Martin del Potro and Leonardo Mayer 6-1 3-6 6-4 6-4 in front of a loud and passionate crowd to reduce Britain's arrears to 2-1 in the semi-final against Argentina.

Defending champions Britain must now win both the reverse singles rubbers on Sunday if they are to pull off what would be the most remarkable of all their recent victories.

The Murray brothers were given a huge ovation as they prepared to do an on-court interview, and Jamie's voice cracked as he said: "It's not going to get better for me than to play with him in front of a Scottish crowd."

The 30-year-old doubles expert left the arena on Friday during Andy's titanic tussle with Del Potro to attend their grandfather's funeral.

"It's been a tough week for us but we just had to try to park it for the afternoon and focus on what we needed to do," said Jamie.

"It's one of those things you have to go through in life. It's not easy but I think we did a good job of getting out there and performing well and fighting as hard as we could, and we deserved the win in the end."

Jamie was playing in his first match since winning his third grand slam title at the US Open last weekend alongside Brazilian partner Bruno Soares, and he oozed confidence.

He was the best player on the court throughout the match, his sublime volleys helping Britain race into a 5-0 lead.

Andy Murray played a poor game to drop serve early in the second and the brothers looked in trouble when the world number two singles player was broken again at 3-3 in the third.

But that proved the catalyst for them to seize the momentum, Andy using the crowd to raise his depleted energy levels and conjuring some fine returns.

The main talking point before the match had been whether he would play after spending five hours and seven minutes battling and losing to Del Potro on Friday, the longest match of his career.

"I didn't know how I was going to feel when I woke up," said Andy Murray.

"I saw my physio this morning and he checked some of the things he checks if I'm not feeling great or if I'm tired and he said I was looking decent.

"It was tough, obviously. In doubles there's not as much running but you need to be very sharp."

While it was not too much of a surprise to see Britain's talisman out there, Del Potro's presence was unexpected given Argentina's position in the tie and the fact their star player is still working his way back from two years out through injury.

Captain Daniel Orsanic explained: "I thought that it was the best doubles we could go with. We went for it to intend to close the tie."

It was a gamble that did not pay off, and Del Potro even hinted he may not play should the tie go to a deciding rubber on Sunday.

The odds are that will happen, with the first match pitting Andy Murray against world number 49 Guido Pella.

Murray is clearly fatigued but is confident he will have enough, saying: "I think so. Whether I win or not, I don't know, but I can definitely guarantee I'll give my best effort and hopefully I can.

"I'll be tired and I have to accept that and deal with it and try to play the match on my terms if possible."

Del Potro returned to the tour in February after three wrist operations and has been taking his comeback slowly, choosing to miss the French Open for example.

He said: "Of course I didn't expect to play eight hours in two days. It's enough for myself at this moment of my comeback.

"This weekend I did a big effort and hopefully I can finish the week healthy. It would be a risk if I had to play a match like yesterday. If something happened to me in this situation, I would be really, really sad because I fought a lot to come back to tennis.

"I have to be smart because this is just the beginning. I want to play for more years, not just one more match."

If Del Potro does not play, Argentina can call on either Federico Delbonis or Mayer, while Britain are likely to select Dan Evans ahead of Kyle Edmund, who was disappointing in defeat to Pella on Friday.