W hen Duke Paluch gives a lesson to a young tennis player, he inevitably makes reference to the 155-mph then-record serve Andy Roddick hit in the 2004 Davis Cup semifinals, which remained the fastest serve in the world until 2011.
Roddick, who lost to Juan Martin del Potro of Argentina in the fourth round of the U.S. Open on Wednesday, retired after more than a decade of professional tennis, saying after the match that he "loved every minute" of the game.
Roddick served as a spokesman for Babolat, headquartered in Louisville, for much of his career. He played with a "Pure Drive" racquet, which is one of the top-selling Babolat racquets in the U.S., according to Babolat spokeswoman Susan DiBiase.
"Andy's been a great ambassador for the brand," DiBiase said. "He was the first high-profile American player to use a Babolat tennis racquet."
For many players, Roddick's technique was something to emulate on the court. And for or many teaching professionals in Boulder, Roddick will continue on as a household name.
"As a teaching pro, you're constantly talking about the Roddick serve," said Paluch, director of Rocky Mountain Tennis Center in Boulder.
Roddick announced last week that the U.S. Open would be his last tournament, to much of the tennis world's surprise. The Omaha-native won 32 tournament titles, including a 2003 win at the U.S. Open, and led the United States to the 2007 Davis Cup championship.
He won two titles in 2012, and finished his career ranked No. 22 in the world -- facts that left many puzzled about his decision to retire when he was still a viable competitor.
"I do think he could've stayed on," said Meadows Club Director of Tennis Adrian Games. "He's still got all the game in the world."
While some teaching professionals used Roddick's technique to teach youngsters, Games says it was Roddick's personality and spirit that helped draw people to the game.
Without Roddick, Games said, fewer people would be watching and playing tennis today.
"He brought an excitement to the kids," Games said. "They liked his style. The biggest loss will be not having Roddick out there for people to root for."
At the Boulder Country Club on Wednesday, people gathered around the TV to watch Roddick play his last match and then make a tearful goodbye speech.
Boulder Country Club Director of Tennis Jon Winegardner said he wondered who would fill the void Roddick has left for U.S. professional tennis.
"It's disappointing," Winegardner said. "It's very telling for men's U.S. pro tennis. People think 'Who's left in terms of American pros?' There's really not a big name out there. He's kind of the last one."
Kendall Chitambar, who works on player development at the Rocky Mountain Tennis Center in Boulder, said he remembers Roddick when he won the 2003 U.S. Open at age 21.
Chitambar remembered the "young, colorful, brash teenager wearing a visor with spiked hair," and wondered if he would flame out after one big win, like so many players.
"I thought he was going to be a flash and then be gone," Chitambar said. "He proved me wrong and he proved so many people wrong, and just became this force for American tennis."
Follow Sarah Kuta on Twitter at @SarahKuta.