IVO KARLOVIC is a Croatian colossus who stands 6ft 11in tall and hits a big ball.

Unfortunately for the 36-year-old from Zagreb, not only is Andy Murray head and shoulders above him in most phases of tennis, he also had the misfortune yesterday to encounter him not far off the height of his powers.

There was to be no act of giant killing on Centre Court. As expected, Goliath only briefly got a look in. It is Murray, a 7-6 (7), 6-4, 5-7, 6-4 winner, who walks tall into his eighth successive Wimbledon quarter final. As big an obstacle as Karlovic threatened to be to his hopes of a second SW19 title, the Scot lobbed him with impunity and by the end seemed to be doing so simply to keep himself amused.

For such a big match, with such massive proportions at play, at times the margins were very small indeed. Karlovic's play style leaves little margin for error. Not only is the Croat one of just three men to have beaten Novak Djokovic in this calendar year, he made it past Jo-Wilfried Tsonga in the last round in a match where he hadn't earned a single break point.

Having prolonged matters into a nervy fourth set, we were on serve at 3-3 when a crucial service break was decided by a distance so minute that even Hawk-Eye was hedging its bets. A Karlovic volley struck the very outside edge of the line, or so both players apparently thought, only for the computer to say no. Murray's challenge, made more in hope than expectation, was validated when it was confirmed that the ball had been out by 2mm. The only problem with this, a point the disgruntled Croat was presumably making afterwards, is that Hawk-Eye's margin of error is 3mm.

There is much to admire about this 36-year-old from Zagreb, the tallest man in the men's tour in the Open era and also possessed of its biggest-ever serve, an 156mph delivery back on Davis Cup duty in 2011. Not only has he hauled himself back up through the rankings after a bout of viral meningitis, but playing some of the best tennis of his career, he had made it out of a tough portion of the draw which included Alexandr Dologopolov and Jo-Wilfried Tsonga. An entertaining figure to follow on Twitter, he has battled a stammer, and played here as the oldest player to reach this stage since his countryman Goran Ivanisevic.

While he has sacrificed a bit of speed on his serve these days in order to find more consistency, that mighty serve of his more than lived up to its billing. A total of 29 times those thudding serves eluded Murray's rapier-like reflexes, the Croat's fastest second serve coming in at the same speed, 126mph, as the Scot's second serves. He played his game, and was rightly happy with his tactics afterwards.

The only problem was that most of Murray's play was of another level. Forget about Karlovic's serving arm, we had worried going in about the Scot's sore shoulder, considering that when he was last on court against Andreas Seppi, his back was going like a "machine gun" when Dr Clay Sniteman was manipulating it. Such concerns, however, were unfounded. While he took a smidgeon of juice off it, for those first two sets Murray was getting 81% of his deliveries in play, a huge upturn from numbers in the high 30s at points during this tournament.

Converting break points was a chore, though, usually because those points tended to end with a booming Karlovic serve down the T, such as the one which nearly beheaded a line judge early on. Consequently the first set ended, as Karlovic sets so frequently do, in a tie-break. Seven Scottish set-points had come and gone by the time the 564th such breaker of Karlovic's career was settled in Murray's favour, 9-7. In all, the set had taken 57 minutes to complete.

It might not always have been for the purist but in football terms this match resembled a top four Premiership club being drawn away to a long ball outfit from League Two. The Scot had to play his game, not end up playing Dr Ivo's. This he did by putting on a returning clinic. Karlovic was driven to distraction by the amount of time he had to pick the ball up from his shoelaces or unorthodox positions. He was then at the Scot's mercy, who showed none, merely his full repertoire of lobs and passing shots.

That break of the Karlovic serve that we had waited for so long finally arrived at the start of the second, Murray immediately producing, Karlovic-like, an ace to prevent the Croat from breaking back. He took it 6-4, but with breaks of serve thin on the ground, the third set went the other way. Serving behind in the cycle, Murray played a poor 12th game and one botched backhand prolonged the tension into a fourth set.

Karlovic has twice come back from two sets to love down, but Murray was determined that so-called manic Monday would not become panic Monday. Centre Court exhaled when that break for 4-3 was confirmed by Hawk-Eye, and while one last miracle shot from Karlovic detained him in it a while longer, one last Karlovic return flew long and Murray was into the quarter finals. His opponent, like a father who had just been defeated by his son, congratulated his opponent, then waited sportingly to walk off court. That was the long and short of it.