John Isner found his serving groove early in his Wimbledon match against Italy's Jannik Sinner on Friday to set a new record for the number of aces on the ATP Tour.
The giant American, 37, started his match against the 10th seed four aces behind Croatia's Ivo Karlovic, who has served 13,728.
Isner, who dumped Andy Murray out in the previous round, broke the record in the third game of his match on Court Two with his fifth ace.
Record-keeping began in 1991.
"It's actually really cool," Isner said ahead of Friday's match, looking ahead to breaking the record.
"It's something I'm really proud of. I will be the all-time leader. I'll keep playing, keep adding to my total... I don't know if (the record) will get broken. I could be up there for a long time."
Isner, who stands six feet 10 inches (208 centimetres) tall, is also in the record books for taking part in the longest match in tennis history in 2010, against Frenchman Nicolas Mahut.
A plaque was unveiled outside Court 18 at Wimbledon to commemorate the contest, which lasted 11 hours and five minutes.
'Give him another plaque," US tennis great John McEnroe said on ESPN.
stefanos vs Kyrgios
Stefanos Tsitsipas takes on Nick Kyrgios in a blockbuster clash at Wimbledon on Saturday, with the winner likely to be the main obstacle in Rafael Nadal's path to the final.
Fourth seed Tsitsipas is the only other top-10 player left in Nadal's side of the draw, while fiery Australian Kyrgios is a match for anybody on his day.
Tsitsipas's confidence is sky-high after he clinched his first grass-court title in Mallorca last week and he now has an 8-2 record on the surface this season.
The Greek player is facing a man he has beaten just once in four matches.
Kyrgios, who came out on top when the two players met in Halle last month, has been making waves at Wimbledon on and off the court.
His opening win over Britain's Paul Jubb was marred by his admission that he spat in the direction of fans, whom he accused of being disrespectful, and he also took aim at officials.
The 27-year-old, who was fined $10,000 over Tuesday's incidents, has been also in a testy mood in his post-match press conferences but he remains bullish.
"I just feel like I'm comfortable in my own skin," the 40th-ranked player said after his straight-sets win over Filip Krajinovic.
"Some people love to just tear me down. It's just not possible anymore."
Tsitsipas, who reached the fourth round in 2018, said he was "thrilled" to be facing Kyrgios, who beat Nadal on his way to the quarter-finals in 2014.