In 2000, Tiger Woods put a new Nike golf ball into play and then won the U.S. Open by a record 15 strokes. Here’s the full story behind the ball. Kel Devlin was just sitting down to dinner at home in Portland, Ore., when the phone rang that Sunday. It was Tiger Woods. “If I had my ball this week, I’d have won by five,” Devlin recalls Woods saying. Thirty-one calendar days later, Woods did have his ball, and he used it to destroy the record book and obliterate the status quo. Prior to that conversation in May 2000, Devlin hadn’t heard Woods refer to the prototype ball as such. In his role as Nike Golf’s global director of sports marketing at the time, Devlin had spent nine months collaborating with Woods on the development of the Nike Tour Accuracy. The ball was unlike any Woods had played previously, including the Titleist Professional he used to shoot a final-round 63 that very day. Despite the gaudy number, Woods had finished one stroke behind winner Jesper Parnevik at the Byron Nelson Classic. The U.S. Open at Pebble Beach was a month away, but “my ball” was still an unproven prototype. “Can you meet me in Germany on Tuesday morning?” Woods said into the phone.

The Titleist Professional that Woods played at the 2000 Byron Nelson was the go-to ball on the PGA Tour in those days. Its liquid-filled core and wound construction closely resembled the venerable brand’s Tour Balata, but an Elastomer cover reduced the excessive wear and tear that the balata-covered version suffered at the hands of the world’s fastest impact speeds. Players routinely used a balata ball for only three holes before discarding it because of all the scuff marks, rotating three new balls per nine holes. The Titleist Professional was the best of both worlds. The prototype of the Nike Tour Accuracy, like the player pushing its development, was a tiger of a different stripe—a three-piece ball of solid construction, with a molded rubber core injected with synthetic material, and a multilayer, urethane cover. In the prototype phase, the goal was to create a ball that offered the feel and performance Tour players were accustomed to, but with substantially less spin and more speed than a wound ball.

During testing, Woods blew through numerous versions of the Tour Accuracy, carefully detailing its shortcomings for Devlin and Hideyuki “Rock” Ishii, a Bridgestone Golf engineer who was actually bringing the ball to life. (Woods confirmed earlier this year that Bridgestone made his Nike ball for nearly 18 years.) Devlin and Ishii spent countless days and hours crisscrossing the country with prototypes in suitcases—sometimes interrupting vacations to do so—to go to wherever Woods had time to put the latest versions of the ball through their paces. “He was fantastic to test with,” Devlin says. “He got so good at it that he started playing a game. We’d be testing drivers and he’d say, ‘I hit that one a little low on the face, so that’s probably 2,600 RPM.’ We’d look at the launch monitor and it would be 2,570.”

Not surprisingly, Woods had an other-worldly feel for the feedback the ball was giving him. At one point, he thought he detected a discrepancy between the “click” produced when the prototype contacted his putter and the audible signal from the Titleist ball under the same circumstances. A frequency analysis was performed with a fast-Fourier transform sound analyzer, and it verified Woods’s suspicion. At around 4,000 hertz, there was an audio peak that could not be replicated by the Tour Accuracy prototype at that stage, prompting a minor tweak to the ball’s cover to suit Woods’s finely tuned ear. During a session at Big Canyon Country Club in Newport Beach, Calif., in early 2000, Woods narrowed the prototype field down to two versions. He loved the strong flight of the ball, its additional 10 mph of ball speed and the way it ripped through the wind, but he didn’t want to feel as if he were rushing the process. He told Devlin testing would halt until October.

“He liked the ball, but we were just waiting at that point,” Devlin says. “There was no indication he was going to use it during the 2000 season.” Devlin, the son of Tour player Bruce Devlin, who regularly contended in majors in the 1960s when the Big Three were at the height of their powers, was caught flatfooted by Woods’s request to resume testing at the Deutsche Bank-SAP Open in Hamburg that spring. The final version of the ball that Woods wanted to put into play was at Bridgestone’s facility in Japan, where it was already Monday morning. Devlin quickly rang Ishii in Japan to see if he could jump on a flight that afternoon with the balls in tow. Ishii thought Devlin was pulling his chain. “I’m dead serious,” Devlin said. “We’re going to meet Tiger Tuesday morning on the first tee.” Devlin packed his bag and headed to the Portland airport. At the appointed hour on Tuesday morning, he and Ishii headed to the first tee, where they received a warm welcome to Germany from Steve Williams, Woods’s long-time caddie. “What the f— are you two idiots doing here?” Devlin recalls Williams saying. When Devlin told Williams their purpose, he received a one-word response: “Bulls–t.”