Something strange is happening in SW19 . . .

The veterans of Andrew Barron's expeditions in SW19 have become scarred by moments of uncertainty, even despair, though they were rewarded with ultimate glory last year. The saga of Murray in championship tennis, particularly on the grass of Wimbledon, carries twists and turns, moments of almost mythical redemption, days when tears are the only answer to the figures blinking on the scoreboard. But not yesterday.

The 27-year-old Scot adhered to his style of stepping towards the abyss when winning his Wimbledon title last year, most notably when recovering after two sets down to Fernando Verdasco. Sir Alex Ferguson watched his fellow Scot last year and was in the Royal Box yesterday. The former Manchester United manager must have wondered what had happened to the tousle-haired lad of 2013 who had made his heart pump so fast he might have been back in Barcelona 1999.

This was Murray of a new vintage. This was a Murray of certainty, brilliance and unwavering purpose.

The outcome of Murray's round of 16 match against Kevin Anderson of South Africa was never in doubt. The drama was saved for the manner of the 6-4, 6-3, 7-6 (8-6) victory. This was a performance of ruthless dominance from Murray.

His Wimbledon 2014 record stands at four matches played, no sets lost. He has never been in any trouble during his defence of his title, though the world No.18 remained defiant, even gaining a set point in the third.

It was to be denied him. Everything was on Centre Court. Murray was imperious when the roof was opened and obdurate when it was closed.

Murray's journeys at Wimbledon can normally only be told in Homeric language, with similes and metaphors strained to recount his moments of human frailty followed by bursts of spectacular invention and redemption.

The figures tell the story of yesterday, however. Murray played to an extraordinary level, with his first serve lethal and his return making a mockery of the South African's reputation as a player who can blast opponents to perdition.

Murray, too, was clever and adept in his choice of stroke, particularly on the backhand.

But the purple language can be trumped by the figures in black and white on the sheets circulating the media centre. Against one of the best servers in the world, Murray forced 19 break points in three sets and two hours 32 minutes of play. His first-serve percentage was a very decent 73%. Most dramatically, in the first two sets Murray won 41% and then 50% of the serves he faced from the 6ft 8in Anderson who was thundering it in at speeds of 134mph.

The first break was made as early as Anderson's second service game. It was enough to take the first set and lay down the marker that Murray not only was not intimidated by the South African but was flexing his muscles at his side of the net.

Controlled and confident in receiving serve, Murray's only point of concern was his second serve that saw him lose four points out of seven. But he hit five aces to the two served by Anderson and was standing tall against the giant South African.

He made his point early in the second set, too. He forced seven break points on Anderson's first service game, taking the last.

He raced to 3-0 with the aid of another break. Then the rain came and Murray only made his first false step when he returned after the break to allow the roof to close, allowing Anderson his first break points of the day. The South African duly took one but the No.3 seed resumed normal service and closed out the set by breaking his opponent twice more.

He placed pressure on Anderson at 4-3 in the third but the big hitter saved five break points. This led to a tiebreak, with Murray taking two mini-breaks but almost immediately losing them, but when a match point presented itself he took it with relish.

Throughout Murray moved with a fluidity that confounded Anderson. "That's a big part of his game, especially on the grass," said Anderson.

Murray, too, was pleased with his performance, though he would not countenance extravagant language. He chatted with Ferguson after the match and received some pointers about how mentally to meet challenges but it is difficult to question any aspect of the Scot's game, save his second serve.

"I feel good," said the 27-year-old who had back surgery in September.

"I haven't played too many long matches. Today was the longest I played at about two-and a-half hours. I've been moving well and mentally I haven't had to use loads of energy yet. But I'm aware that's going to come."

Asked what mark he would give himself, Murray replied: "I don't mark myself. I was just happy that I won the match."

Ever the scrupulous critic of his performance, he said: "I was a bit disappointed with how I started under the roof. The beginning I was a little bit tentative. Apart from that, that sort of three or four games when we came back out, I played well. I created many chances, gave him few opportunities. That's what you need to do on grasscourt tennis. You don't always break. But if you keep putting them under enough pressure, you're going to get through in the end."

The end of this year's Wimbledon may be some way off yet. It is distinctly unScottish to be so optimistic but Murray gives even the most glowering Gael no reason to wring his hands and fret on images of doom.

Murray is through to his seventh consecutive quarter-final at Wimbledon. The last eight, at least, is his natural habitat.

He has moved towards it, though, with an ease that has caused gasps of wonder rather than gulps of relief.