DeeDee Trotter ran the fastest women's 400 metres in the world this year and ended the 18-race winning streak of world silver medallist Sanya Richards at the US championships on Saturday.
Trotter, fifth-place finisher in the 2004 Olympics and 2005 world championships, came from third off the final bend to claim the win in a lifetime best 49.64 seconds.
Natasha Hastings finished second in 49.84, with Mary Wineberg third in 50.24.
A struggling Richards, who has been suffering from a flu-like illness this year, placed fourth in 50.68.
World silver medallist James Carter provided another world leading time, winning the 400 metres hurdles in 47.72 seconds. Kerron Clement was second in 47.80 and Derrick Williams third in 48.26.

Five best throws
World indoor champion Reese Hoffa had the five best throws to win the men's shot at 21.47 metres. Dan Taylor was second (21.00) and Adam Nelson third (20.54).
Angelo Taylor was first in the men's 400 metres in 44.05 seconds. He was followed by LaShawn Merritt in 44.06 and Lionel Larry in 44.84.
Ginnie Powell won the women's 100 metres hurdles in 12.63 seconds. World champion Michelle Perry was second in 12.72, with Lolo Jones third in 12.79.