Kastor, 41, ran her fastest half marathon since 2010.

Deena Kastor is starting to get into a groove again, and that means the U.S. masters record book could be in trouble.

The 41-year-old Kastor won the 2014 More|Fitness Half-Marathon in New York’s Central Park on Sunday in a U.S. masters record of 1:11:38. After coming close to the record and missing last month at the Rock ‘n’ Roll Dallas Half Marathon, Kastor broke the 2006 mark held by Colleen De Reuck (1:11:50) by 12 seconds.

The three-time U.S. Olympian took the lead from the start and was never challenged. Tsehay Getiso, an Ethiopian runner who lives in New York, was second in 1:15:07. Kastor ran her fastest half marathon since before having a baby in 2011, and she did it on a course that wasn’t exactly flat.

Last year, Kastor placed third at the LA Marathon in 2:32:39 and then went on to place ninth in the marathon at the IAAF World Championships in 2:36:12. Although she said that might be her last high-level marathon, she’s certainly still among the best half-marathoners in the U.S.

Among American runners, only Molly Huddle (1:09:04), Annie Bersagel (1:10:10), Lauren Kleppin (1:10:16), Serena Burla (1:10:48) and Desiree Linden (1:11:37) own faster half-marathon times than Kastor this year.

Kathy Martin, another American masters running ace, placed 12th overall in 1:29:23, about a minute off her own U.S. 60-65 age-group record.