2013 Wimbledon champion Andy Murray outlasted the big serving of Croatia's Ivo Karlovic to reach the quarter-finals, while seven-time champion Roger Federer beat Spain's Roberto Bautista Agut to also advance at The Championships on Monday.
France's Richard Gasquet defeated Nick Kyrgios to avenge his second-round defeat to the Australian in the second-round of Wimbledon last year, while French Open champion Stan Wawrinka continued his progress through the draw, beating Belgium's David Goffin to book his place in the quarter-finals.
Karlovic's serve, which comes hurtling down from his giant 6'11" frame, is one of tennis's most terrifying weapons, but it was not enough to stop the third seed moving on with a hard-fought 7-6(7) 6-4 5-7 6-4 victory.
Modern grass-court tennis these days requires so much more than just a fearsome opening delivery, and Murray, who has now reached the last eight for the eighth consecutive year, is one of the game's most skilled returners.
Although he did drop a set, he never looked truly troubled by the Croat, whose all-round skill set is lacking in some key departments.
Karlovic was hardly an unknown quantity for Murray. At 36, he has been around a while and is the oldest player to reach the last 16 at a grand slam since a 39-year-old Jimmy Connors did it at the US Open 24 years ago. The pair had also met five times previously with Murray winning every one, which included a skirmish at Wimbledon three years ago.
Yet knowing what to expect when facing Karlovic, does not make him any easier to master.
"It was an incredibly difficult match, it was mentally tiring because you just have to be ready when the chances come," Murray said having teed up a clash with Canada's Vasek Pospisil.
The towering Croat fired down 29 aces, which by his standards was a poor return given he had walloped 136 in his first three matches. From the start, he was launching 130mph missiles, but Murray's keen eye was picking them up in the afternoon sun, and the Briton moved quickly into a two-set lead.
However, a cat-and-mouse third set was decided when Karlovic broke in the 12th game, dampening the glee of the locals on Centre Court but injecting some much-needed life into the match.
With his enthusiasm rekindled, Karlovic then dug in, holding serve comfortably until Murray sniffed his chance and broke for a 4-3 lead in the fourth. After passing up a chance to break back, Karlovic was swiftly facing match points, saving one on his own serve before Murray closed it out in the following game as the Croat swiped a forehand long.
Roger Federer of Switzerland reacts after breaking serve during his men's singles fourth-round match of the 2015 Wimbledon Championships against Roberto Bautista Agut of Spain at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. (Reuters Photo)
Federer's pursuit of an 18th Grand Slam title gathered momentum as the Swiss reached his 45th major quarter-final with a serene 6-2, 6-2, 6-3 victory over Bautista Agut.
Breaking Federer's serve at this year's championships is turning into mission impossible as Bautista Agut became the fourth man to try and fail.
The world number two has now held strong for eight straight matches, stretching over 106 successive service games -- with Germany's Philipp Kohlschreiber the last man to get a look in during last month's first-round match at the Gerry Weber Open in Halle.
A netted backhand by Bautista Agut on his own serve completed the most straightforward of wins and earned Federer a quarter-final date with French 12th seed Gilles Simon.
Richard Gasquet of France celebrates winning his men's singles fourth-round match of the 2015 Wimbledon Championships against Nick Kyrgios of Australia at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. (Reuters Photo)
Gasquet avenges Kyrgios defeat
Gasquet avenged last year's painful Wimbledon loss against Kyrgios as the French 21st seed moved into the quarter-finals with a 7-5, 6-1, 6-7 (7), 7-6 (6) victory. Gasquet had wasted nine match points while squandering a two-set lead in a second round defeat to Kyrgios 12 months ago.
But the 29-year-old made amends on Court Two with a powerful display against the 26th seed, who helped the Frenchman by appearing to deliberately lose several points in the second set.
Gasquet, who made the semi-finals in 2007, will play Wawrinka for a place in the last four. Gasquet's victory also improved his miserable record in Grand Slam last 16 ties -- he had lost 16 of his previous 18 matches at that stage. The 29-year-old's vast natural gifts have yet to bring sustained success, with his best runs at the majors ending in semi-final defeats at Wimbledon and the US Open two years ago.
Kyrgios had earned a reputation as something of a malcontent during the first week of the tournament as he argued with umpires, shouting out 'dirty scum' during one row, bounced a racket into the crowd, and claimed he didn't care if he was fined or how people viewed his antics. The brash 20-year-old looked in the groove when he broke in the opening game of the match, but Gasquet was unfazed, hitting back in the fourth game and going on to take the set with his second break.
Kyrgios was reduced to applauding admiringly when Gasquet unfurled yet another sublime backhand winner late in the first set. And when he blurted out that "I might as well just leave now", it signalled one of the volatile Kyrgios's infamous mood swings, with Gasquet quick to punish the Australian's lack of focus.
He broke in the second game of the second set and Kyrgios responded petulantly -- appearing to 'tank' in the next game as he walked in the opposite direction to one Gasquet serve and then gently knocked another return into the net.
Kyrgios broke early in the third set, only to let Gasquet off the hook when he dropped serve soon after -- reacting to that failure in typically eccentric style by hugging a ball-boy. After saving two match points at 5-6, Kyrgios made the most of his escape to take the tie-break.
But Gasquet kept plugging away and finally saw off the Australian in the fourth set tie-break.
Stan Wawrinka of Switzerland celebrates winning his men's singles fourth-round match of the 2015 Wimbledon Championships against David Goffin of Belgium at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. (AP Photo)
Wawrinka back in quarters
Wawrinka continued his pursuit of a rare double with an air of calm authority, beating Goffin 7-6 (3), 7-6 (6), 6-4.
The fourth seed, bidding to emulate fellow Swiss Roger Federer and become only the fifth man in the professional era to win the French Open and Wimbledon back-to-back, turned on the style on a sun-swept Court One.
Wawrinka is yet to drop a set so far, although Goffin forced the 30-year-old to produce some of his best tennis.
Sixteenth seed Goffin, in the fourth round for the first time, had a point to level the match at one set apiece and was a break ahead in the third set before Wawrinka reeled off a succession of brilliant backhands to close out victory.
Leading 5-4 on the Goffin serve, Wawrinka dug out a glorious backhand down the line to move 0-30 ahead and, when Goffin double-faulted to offer up match points, Wawrinka ended the contest with a similarly spectacular forehand.
Gilles Simon of France celebrates after winning his men's singles fourth-round match of the 2015 Wimbledon Championships against Tomas Berdych of the Czech Republic at The All England Lawn Tennis and Croquet Club in London, on July 6, 2015. (Reuters Photo)
Simon upsets Berdych
Simon will play in the Wimbledon quarter-finals for the first time after beating 2010 Wimbledon runner-up Tomas Berdych 6-3, 6-3, 6-2.
Simon has only once before reached the quarter-finals at a major tournament, getting that far at the 2009 Australian Open. And Wimbledon had been the 30-year-old Simon's worst Grand Slam. He only got as far as the fourth round once before, also in 2009.
In other results, unseeded Vasek Pospisil became only the third Canadian man to reach the quarter-finals with a 4-6, 6-7 (4), 6-4, 6-3, 6-3 win over Serbian 22nd seed Viktor Troicki. Pospisil follows Robert Powell (1908, 1910 and 1912) and Milos Raonic (2014) as the only Canadian men to have reached the last-eight at the All England Club.
US Open defending champion Marin Cilic beat Denis Kudla of the United States 6-4, 4-6, 6-3, 7-5.
(With inputs from AFP, AP and Reuters)