The international woman of mystery proceeded to become a familiar, prolific medal-winning figure when she stepped into the major championship arena. Between 2003 and 2008, Ndereba finished in the top two in five successive global championship marathons.
She claimed gold at the World Championships in Paris in 2003 and in Osaka in 2007, taking silver behind the victorious Radcliffe in Helsinki in 2005. At Olympic Games, she finished runner-up to Japan's Mizuki Noguchi in Athens in 2004 and to Constantina Tomescu-Dita of Romania in Beijing in 2008.
Another product of the Kenyan Prisons Service women's marathon squad, Margaret Okayo was unable to make her mark at major championship level, registering a DNF in her one marathon appearance, at the 2004 Olympics. But like Ndereba, her teammate in the Greek capital, her exploits at 26.2 miles also went somewhat underappreciated.
Four years younger than Ndereba, Okayo won four World Marathon Majors: New York in 2001 (a 2:24:21 course record), Boston in 2002 (a 2:20:43 course record), New York in 2003 (2:22:31, another course record) and London in 2004 (2:22:35). She also finished runner-up in Chicago in 1999 and third in New York in 2000.
Her winning time in Boston in 2002 stood as the course record for 12 years, until Ethiopia's Bizunesh Deba sneaked inside 2:20 with 2:19:59 in 2014. Okayo's performance was the product of a gripping duel with Ndereba.
The pair ran mostly side by side from just past halfway until Ndereba's right hamstring started to tighten with two miles to go. Okayo pulled clear to win by 120m in 2:20:43, beating Uta Pippig's 1994 course record of 2:21:45.
Ndereba was also inside the German's old mark with 2:21:12 in second place - faster than all four of her winning times on the undulating course.
Okayo set course records during three of her four World Marathon Majors victories. Her 2001 New York win in 2:24:21 took 19 seconds off the course record that Lisa Ondieki had set in 1992.
After breaking the Boston course record in 2002, Okayo returned to New York and smashed her own race record with 2:22:31 - a mark that still stands today and has withstood the challenge of some of the world's best distance runners, despite them having the benefit of improved shoe technology.
As was the case in Boston one year prior, Ndereba finished second with a time well inside the previous course record (2:23:03).
That 2:22:31 run remains Okayo's lifetime best, but the fact it was achieved on New York's challenging course suggests she would have been capable of a much quicker time that day had she been racing on a flatter and simpler route.
Ndereba's fastest marathon time, of course, was her 2001 world record run in Chicago. Just seven days after Japan's Olympic champion Naoko Takahashi had breached the 2:20 barrier with a landmark 2:19:46 clocking in Berlin, Ndereba flew to a finishing time of 2:18:47 in the US's Windy City.
She ran the first three miles at 5:45 pace, then accelerated to 5:15 in the fourth mile and held her speed the rest of the way. She finished over six minutes clear of her closest pursuer, Alemu filling the runners-up spot in a distant 2:24:54.
"Takahashi's run in Berlin made it so much easier for me," Ndereba maintained. "It was like she broke a barrier. Before, women didn't think we could go under 2:20. In future, the next generation will run under 2:18. Maybe they will break 2:15 one day."
Ndereba was a breaker of major barriers herself. When her daughter, Jane, turned one, she left her at home in Nairobi with her husband, Anthony Maina, for three months each year. Setting up base in Norristown, Pennsylvania, and spending a quarter of her year competing on the US road-racing circuit attracted criticism back home.
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"If you don't have anything to sacrifice, you don't have anything to gain," Ndereba said. "This is my career. There is no way you can tell one of your kids not to go ahead with his or her career."
Jane was 10, old enough to accompany her mother on her travels, when Ndereba emerged victorious from a gruelling thriller of a World Championship marathon race in the stifling heat and humidity of Osaka in 2007.
Asked about the oppressive conditions, Ndereba remarked: "If I had been able to run naked today, I would have." After pausing for further consideration, she added: "Unfortunately I couldn't, because my daughter was here watching... She wouldn't like it if her mother was running without her clothes on."