Andy Murray beats Kevin Anderson under Wimbledon roof

Defending champion Andy Murray overcame the big serving of 20th seed Kevin Anderson to reach the Wimbledon quarter-finals for the seventh time.

Murray won 6-4 6-3 7-6 (8-6) in a match that ended under the Centre Court roof after a rain delay in the second set.

The Briton has yet to drop a set and will next face Queen's Club champion Grigor Dimitrov in the last eight.

Murray, 27, has now won 17 consecutive matches at the All England Club, stretching back to London 2012.

He remains on course to defend his Wimbledon title and so match Fred Perry, the last Briton to do so in 1936.

The Scot saved a set point with a big serve in the third set tie-break as Anderson came out firing after the rain break, but he has barely put a foot wrong on his way into the last eight.

"When it was outdoors I played very well and was in a good position, but when we came indoors he was striking the ball better and serving better and I was dropping shorter," Murray told BBC Sport.

"That meant there was a lot more running at the end because he was playing very well."

Anderson, 28, posed an obvious threat on serve at 6ft 8in, and with 63 aces in his first three matches, but his greatest weapon played into Murray's strength.

The South African was under pressure as early as the third game at 0-40, and when Murray managed to block back a 130mph serve on the third break point, it was no surprise that Anderson faltered in the rally that followed.

Murray saw out the set after 43 minutes, and the pressure on Anderson only increased at the start of the second set.

After a couple of flashes of frustration, the Briton eventually converted his seventh chance of the opening game when Anderson steered a volley wide, and the threatening skies above Centre Court looked to be the world number 18's best hope of disrupting the champion.

With spectators reaching for their umbrellas, Murray broke again to lead 3-0 before play was halted, and it proved crucial when the action resumed half an hour later.

Anderson came out determined to make an impact on the Murray serve and did so immediately, reclaiming one of the breaks and then earning himself a point to level at 3-3.

It had been an edgy 10 minutes for Murray since the resumption and he was in danger of being dragged into an unexpectedly close contest, but a bold second serve right onto the line averted the danger.

Murray broke for a fourth time to move two sets clear and, while Anderson was a tougher proposition in the still, indoor conditions, he could not hold off the two-time Grand Slam champion.

Five more chances slipped by at 4-3 as Murray's break-point conversion rate fell to four out of 19 for the match, and he saw off a set point in the tie-break to clinch victory with a heavy backhand into the corner.

"I knew I was going to get tested at some stage," added Murray.

"Today I was pushed, especially in the middle part of that second set, then obviously later on in the third there were some tight moments. But I handled them fairly well. It was a good match."

Murray had a 1-1 record against Anderson going into Monday's match, their first meeting on grass

Sir Alex Ferguson was among those in the Centre Court Royal Box to watch the defending champion

Anderson struggled in the early stages, dropping serve three times before the rain came

Spectators on the hill took shelter as rain stopped play on Centre Court for half an hour

Murray found it harder going under the roof but took his first match point in the tie-break