Ivo Karlovic set a US Open record on Tuesday when he banged down 61 aces on his way to a first round victory over Taiwan's Yen-Hsun Lu.
The 37-year-old Croat, who has served the most aces in ATP Tour history with well over 11,000, hit 22 in the second set alone as he outgunned Lu 4-6 7-6 (7-4) 6-7 (7-4) 7-6 (7-5) 7-5 .
Tuesday's total beats the previous record of 49 set by Dutchman, Richard Krajicek, in the quarter-finals in 1999.
"I knew there were a lot of aces because at one stage I was serving one on almost every point but I didn't know it was a record," Karlovic said.
Only 10 of the aces came in the final set but Karlovic broke to win the match.
"I'm getting old," he joked.
"I have to work a bit more on my serve, I guess."