LaShawn Merritt raced to the top spot in Sunday's 400 meter dash at the USA Track and Field Olympic Trials to earn the right to defend his gold medal in London.

Merritt finished the race in 44.12 seconds to edge Tony McQuay's 44.49. Bryshon Nellum came in third with a 44.80.

The top three finishers in each race qualify for the Olympics.

Merritt captured the gold in 2008 with a time of 43.75 seconds and will be seeking a repeat in London.

Sanya Richards-Ross took the top spot in front of Dee Dee Trotter and Francena McCorory with a time of 49.28 seconds in the women's 400 meter dash to earn their place on the American team.

Later, Justin Gatlin edged Tyson Gay by .06 seconds in the 100 meter dash to secure his place on the squad. Ryan Bailey placed third in the event to earn his spot.

Other qualifiers on Sunday included Jennifer Suhr, Becky Holliday and Lacy Janson in women's pole vault; Stephanie Brown Trafton, Aretha Thurmond and Suzy Powell-Roos in women's discus throw; Marquise Goodwin, William Claye and George Kitchens Jr. in men's long jump; and Reese Hoffa, Ryan Whiting and Christian Cantwell in men's shot put.