Ben Shelton, despite being only 22, has already established himself as a player widely regarded for his powerful serves. A fan unfortunately felt the full force of a Shelton serve at the 2025 Mubadala Citi DC Open in Washington, with the ATP No. 8 issuing an apology in the immediate aftermath of the incident. Later, the American labeled the serve the "nastiest" he hit during the third-round match in which the incident took place.On Thursday, July 24, Shelton locked horns with talented Canadian Gabriel Diallo for a place in the quarterfinals of the combined ATP and WTA 500 tournament in Washington. At one point during the match, as the American was about to serve, chair umpire Jimmy Pinoargote urged spectators seated in the first row to be alert during serves because of the high speed at which the balls were bouncing off the hard court."Ladies and gentlemen, if you're sitting in the first row, when the players are serving, please pay attention. The ball is coming really fast," Pinoargote warned.Seconds later, Ben Shelton fired an ace with a wicked curve down the T. The ball bounced up and brushed the leg of a female fan sitting in the first row. Despite the seemingly minimal nature of the contact, the fan appeared somewhat shellshocked at the speed and power of the ball, with Shelton immediately telling her:"Sorry. Are you okay? My bad."Watch the moment below:Later, Shelton shared the moment as an Instagram story and captioned it:"Scary that almost nailed someone... nastiest serve i hit fr"Shelton's Instagram Story featuring his "nastiest serve" admission dated Thursday, July 24, 2025 (Source: Instagram/benshelton)"Speed isn't the answer" - Ben Shelton's 2024 admission on evolution of his serve after switching from college tennis to ATP TourBen Shelton begins his serve motion during a match at the 2025 Wimbledon Championships (Source: Getty)In December of last year, Ben Shelton spoke up about how he had to work hard to adjust his serve to meet the demands of the ATP Tour. The American transitioned from college tennis to the tour in 2022 and found out that simply hitting speedy and powerful serves against "superhuman" players wasn't going to cut it."I’d say that I’m not chasing (serve) speed as much as I was when I came out (as a rookie). A lot of the guys on tour are pretty superhuman. I hit it 148 miles an hour, and if I miss my spot they hit it back. And if I just put it back in the court, they hit it back, with a lot of quality, at my feet. So a lot of times speed isn’t the answer," Shelton said.Up next for Ben Shelton at the 2025 Mubadala Citi DC Open in Washington is a quarterfinal clash against home favorite Frances Tiafoe. Shelton leads the head-to-head with Tiafoe 2-1. However, it was the latter who won the pair's most recent meeting at last year's US Open.