BOSTON — Magdalena Lewy Boulet could not hear the footsteps during the last of the 23 sun-kissed miles she had boldly run alone and in front at the women’s United States Olympic marathon trials. But she sensed that Deena Kastor was swiftly encroaching, a champion in waiting.

Kastor had panicked that she might have waited too long. As the American record-holder in the marathon and the reigning Olympic bronze medalist, Kastor, 35, had all the pressure Sunday.

Lewy Boulet had her dream. Born in Poland, and sworn in as an American citizen in an abrupt ceremony the morning of Sept. 11, 2001, Lewy Boulet has since supported her running career while working full time and raising a son.

With veteran savvy, Kastor tracked Lewy Boulet for six miles and passed her at the 23 ½-mile mark on Memorial Drive. Fueled by that delicious exhilaration, Kastor stormed to the finish line amid the clanging of bells from the Old South Church on Boylston Street, winning the Olympic trials in 2 hours 29 minutes 35 seconds.