LONDON (AFP) - Andy Murray clinched Great Britain's first Davis Cup semi-final berth for 34 years as the world number three's gritty victory against Gilles Simon gave his country an unassailable 3-1 lead on Sunday.

Murray defied the aches and pains assailing his body after playing for three successive days at Queen's Club to grind out a 4-6, 7-6 (7/5), 6-3, 6-0 quarter-final success.

The Scot's 23rd win from 25 Davis Cup singles matches secured a first victory over old rivals France since 1978 and took Britain back to the last four for the first time since 1981.

It was a herculean three hour and 26 minute effort from the exhausted Murray and, having ended Britain's 77-year wait for a homegrown male winner of the Wimbledon singles title in 2013, he now has his sights on another memorable milestone.

After wiping away some tears of joy, Murray, who won both singles matches and the doubles with brother Jamie, said: "It feels unbelievable to get through. I used up my last ounces of energy.

"It wasn't looking good in the second set. I was making too many mistakes but I didn't care how I played. I just wanted to win.

"The whole weekend been fantastic. This team has done amazing things. We are punching above our weight."

Britain haven't won the Davis Cup since 1936 and their last final appearance came in 1978, but they have a golden opportunity to end those barren runs this year.

Britain will host Australia in the last four in September, with a final showdown against Belgium or Argentina awaiting if they see off Lleyton Hewitt and company.

Australia were also the opposition when Britain last won a semi-final in 1978.

France captain Arnaud Clement had hinted he might make a late change to his singles line-up by selecting Richard Gasquet instead of Simon.

But he stuck with the world number 11, which was good news for Murray, who had won 12 of his previous 14 meetings with Simon.

Simon was in good form on grass however, having made the Queen's Club semi-finals and the Wimbledon quarter-finals before routing James Ward in the opening rubber on Friday.

Having ended Roger Federer's run of 116 unbroken service games at Wimbledon, Simon had no reason to feel intimidated by the Murray serve and the 30-year-old made a flying start with a break in the third game.

Vital break

For much of the first two sets, Murray, just a week removed from his run to the Wimbledon semi-finals, looked mentally and physically spent as his recent exertions finally caught up with him against Simon, who had an extra 24 hours rest after being left out of the doubles.

Simon was forced to call for a medical timeout when he hurt his right knee after slipping at 4-3 in the first set.

When Simon eventually resumed he wasn't moving so well, but Murray couldn't take advantage and he wasted two break points to allow the Frenchman to serve out the set.

Boosted by the rush of adrenaline from that escape, Simon punished another sloppy game from Murray to break at the start of the second set.

At that point it looked bleak for Murray, who had been mired in sluggish mediocrity.

Yet the two-time Grand Slam champion somehow shook off his lethargy to secure a vital break in the eighth game, forcing a tie-break that he won after a superb fightback from 4-1 down.

Revitalised, Murray broke in the opening game of the third set, again two games later and a third time with a brilliant lob to leave the stunned Simon trailing by two sets to one.

Murray had all the momentum now and he landed the knockout blow with two breaks early in the fourth set to complete one of the most tenacious wins of his career.