John Isner may be the most well-known ‘giant’ we’ve seen on the ATP Tour in recent years, but two players were even taller.
Being tall in tennis certainly has its benefits, as the giants of the ATP Tour can often be seen smashing unreturnable serves, much to the annoyance of their smaller opponents.
It isn’t always beneficial, however, as whilst service games can go by without a hitch, the speed that they lose as they get taller quickly comes back to haunt them in return games.
This was the case for John Isner, the 6ft 8, big serving giant who could ease through service games with a handful of aces but would sometimes get run ragged by his more agile adversaries.
Isner was one of the most successful giants we have ever seen in tennis, as the American picked up 16 titles during his 16 years on the ATP Tour.
The biggest of which came at the Miami Open in 2018, when Isner took down Alexander Zverev to win his first and only Masters 1000 title.
It came in the best year of the 39-year-old’s career, who also reached his first Grand Slam semi-final at Wimbledon, and rose to a career-high ranking of 8th in the world.
A prime example of what can be achieved as one of the taller players in tennis, but there have in fact been two players taller than Isner who played on the ATP Tour.
Ivo Karlovic: The 6ft 11 Croatian serving king
Standing three inches taller than Isner, Ivo Karlovic was the man who held most of the records that Isner has since broken.
The Croatian won eight singles titles during his time on tour, as he served to his heart’s content, and did so brilliantly.
Fastest official serve: 156 mph
In 2011, Karlovic set what was then a record for the fastest serve in ATP history, at the Davis Cup.
In comparison, the fastest serve we saw in 2024, was Ben Shelton with a 150mph effort at Indian Wells earlier this year.
Karlovic’s record stood for five years before Isner hit a 157mph serve in the 2016 Davis Cup, although Sam Groth unofficially broke the record with a 163mph effort in a challenger tour event in 2012.
Most aces on the ATP Tour: 13,728
In 2015, Karlovic surpassed fellow Croat, Goran Ivanisevic for the most ever aces hit on the ATP Tour, a record which stood for seven years.
The 45-year-old would hit over 1,000 aces a year on several occasions, peaking at 1,447 in 2015, just 30 aces shy of Ivanisevic’s record set in 1996.
Again it was Isner, who would eventually steal the record from Karlovic, as the American retired in 2023, having hit a mouth-watering 14,470 aces.
Most aces served in one match: 78
Karlovic’s record of aces served in a single match didn’t last for long at all, as the 78 he hit against Radek Stepanek in 2009, was quickly surpassed by Isner and Nicolas Mahut in their Wimbledon classic.
Mahut hit 103 aces, whilst Isner hit 113, as the pair set what in the current format looks to be a fairly unassailable record.
Karlovic did get used to hitting a large number of aces, however, as he holds five of the top ten matches with most aces.
Criticism of Karlovic’s style of play
As is the case with many of tennis’ greatest servers, they don’t always make for exciting viewing.
Quick service, and return games, often without the reprieve of thrilling points, drop shots, and passing efforts, can make for a tough watch at times, and Karlovic was the recipient of some fairly harsh criticism at times.
The Croat was called ‘boring’ at various points in his career, but often took it in his stride, not taking the criticism to heart.
In response to a fan saying that they hated watching him, Karlovic responded in his typical sarcastic manner.
“Thanks for watching,” he said.
In response to another fan asking how he could be so boring on the court, but funny off of it, he had another humorous blunt response.
“Because I can,” said Karlovic.
Reilly Opelka: The big serving 6ft 11 American
The only player who could match Karlovic in height, Opelka is the tallest active player on the ATP Tour.
After a long hiatus from tennis, the American returned to tennis in 2023, and Opelka has been working on his game, to return to his best.
In 2022, Opelka reached a career-high of 17th in the world, off the back of a great year in 2021, where he made the final of the Canadian Open, losing out to Daniil Medvedev.
Longest tiebreak in ATP history: 46 points
In the 2016 Dallas Open semi-final, Opelka came up against a familiar name Isner, in a match that would break another ATP record.
Opelka won the contest in straight sets, taking the second-set tiebreaker 24-22, the longest tiebreaker in ATP history, a record that stands to this day.
Reilly Opelka’s 2025 ambitions
After returning to the tour in the last year or so, Opelka has struggled to match the form he showed back in 2021, and 2022.
The American has scored seven top ten wins in his career to date, showing that he certainly has the talent to compete at the top of men’s tennis, but it will be up to him to put it all together in the new year.
Opelka is currently ranked 297th in the world, having won just a single match since the beginning of August.
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