David Knights:, external Great result for GB tennis to beat USA in the Davis Cup!

Rob George:, external Murray is so good he's even finished the tie to help the Americans get home to watch the Super Bowl!

Dom Inglot: "Actually playing on the court is fantastic and playing for your country and singing the national anthem was incredible."

Leon Smith: "Andy was superb there. Sam came out swinging, playing risk-free tennis. Once Andy started to move the ball around more he tired out Sam.

"But this is a massive team effort. People don't see the work off the court. We should be proud of the team spirit and what the guys have achieved here. I was saying to the guys during the week that we've used 11 different players over the last few years - a true team effort. It's great to have this team spirit running through."

James Ward: "Andy had to produce today but I was glad I delivered on Friday. Once it moved to 6-1 in the third I had full confidence in Andy to get this done."

BBC Radio 5 live

Image source, Getty Images

Murray: "He came out playing extremely aggressively, especially on my serve. I changed tactics at the beginning of the third set and I was able to dictate many of the points after that. So that change of tactics helped.

"You have a responsibility to your team-mates to play well, but I also have a lot of experience in the Davis Cup and the Slams, so you know how to deal with it relatively well."

Ross Hutchins
British doubles player on BBC Three

"A superb performance form Murray and before him Ward. Well deserved, and I'm thrilled. How well did Murray play at the start of the third set? He was frustrated and annoyed at himself and started playing exceptionally well."

So just to clarify, Great Britain are through to the quarter-finals and a trip to Italy on 4-6 April. The result also means that Britain are guaranteed a first-round place in the 2015 World Group and will not face a play-off.

Murray opens with a drive-volley but then nets a mid-court forehand for 15-15. He looks to have gone long but umpire Molina checks the mark and says replay the point, which has Courier off his seat. It makes little difference as Murray breaks a string and goes long to fall 15-30 behind. Double-fault, and it's 15-40 and two break points for Querrey... a wild and wacky rally follows, with both men having their chances before Querrey nets a backhand. Break point number two... and Querrey hits a forehand long.

Deuce, and Murray opens up a gap before firing over a forehand winner. Match point.... and Querrey's return goes wide! A huge cheer from Murray as he takes Britain into the Davis Cup quarter-finals. Cue hugs and celebrations....

Murray whips a forehand around Querrey at the net, and pounds away at the American from the baseline for 15-30. Querrey gets back on level terms with a serve, and Murray just catches the net cord with a forehand. Querrey goes wide with a forehand and it's deuce. Murray races in to guide a backhand past Querrey at the net and it's match point.... but two big serves help the American escape and prolong the contest.

Querrey hammers away at the Murray backhand and eventually works enough space to try for the forehand down the line, but whacks it long with Murray homing in anyway. A sharp half-volley off his toes on the baseline helps Murray to close out the game. History beckons, everyone - 79 years since victory over the USA, 28 years since a World Group win...

John McKay:, external I wish I had a fiver for every game Andy has won from 15-40 down. Ice in his veins.

Matthew Fergusson:, external Come on Murray, bring it home!

Murray looks ready to pounce after Querrey slips to 0-15 and gives the Briton a gap to aim at, but Murray misses the forehand. The pressure is still on at 15-30 and Murray plays a breathtaking drop shot off the back foot for 15-40. Two break points... and Murray returns a smash with a lob, works his his way in and draws the error. Brilliant stuff.

Great stuff from both men at 15-15, Querrey playing a cross-court forehand that Murray sprints to return behind the American. A terrific backhand lob and a backhand cross-court winner show that Murray is still 'in the zone'. Which is tennis-speak for 'playing well'.

Jeff Tarango
Former American tennis player on BBC Radio 5 live sports extra

"This is where the wear and tear of playing on clay starts to affect the players. You simply don't feel as good on the surface as you did before. Let's see how this affects both players."

Querrey holds to love with a nice half-volley, and it feels like we're going through the motions as we await the business end of the set.

Murray holds to 15, a net cord finishing the job, and Querrey heads to his chair for a glug of pink liquid and some Courier talk.

Querrey thumps away a smash for a love hold, and Murray stumbles at the baseline before shaking his head at something.

John Lloyd
Former British number one on BBC Three

"Andy Murray's body language is so much better than it used to be. It used to throw out a message to his opponent, who loved every minute of it. Now, by and large, and since Lendl came on the scene, he's almost entirely cut it out."

Querrey suggests he might be up for the comeback when he gets to 15-40 and two break points at the start of the fourth, but Murray sees off the danger and lets out another "Come On!"

Image source, Getty Images

Two hours and 16 minutes gone, and it's a long way back for Querrey from here.