NEW YORK: Big-serving American John Isner will call it a career after the upcoming U.S. Open, the ATP Tour’s all-time ace leader announced on Wednesday. Isner, 38, turned pro in 2007 and reached a career high of world number eight. He won 16 singles titles, the biggest being the Miami Open crown in 2018, his most successful season. “After 17+ years on the @atptour, it’s time to say goodbye to professional tennis,” Isner said on social media site X, formerly known as Twitter. Isner added: “The @usopen will be my final. Time to lace ’em up one last time.” The towering North Carolina native crushed an ATP-record 14,411 aces in his career and has the fastest serve ever officially recorded, a 157.2 mph (253 kph) bomb he unleashed in the first round of the 2016 Davis Cup. He came out on the winning side of the longest pro tennis match in history, which lasted 11 hours and 5 minutes and took place over three days at Wimbledon in 2010. The All-England Club was also the site of his best result at a Grand Slam tournament, having reached the semifinals in 2018. He twice made the U.S. Open quarters, in 2011 and 2018.