Kelli White destroyed the opposition as she won her second gold medal of the championships in the women's 200m final.
The 26-year-old won in a time of 22.05 seconds - the fastest time of the year - ahead of Russia's Anastasiya Kapachinskaya while US team-mate Torri Edwards took bronze.
White - who won the 100m on Sunday - used her speed to devastating effect, bursting out of the blocks and speeding clear of her rivals before running a superb bend.
And the American held her form well in the finishing straight to finish well clear of the chasing pack.
"It was a great field and very tough," said White, who took bronze in the 2001 final.
"I am happy but I am just really really tired as it is my eighth race of the championships."
French European champion Muriel Hurtis tightened up and faded into fourth in the final 20m while former world champion Zhanna Block finished fifth.
White became the first woman since Germany's Katrin Krabbe in 1991 to win both the 100m and 200m at the world championships.
Women's 200m results
1 Kelli White (US)22.05secs
2 Anastasiya Kapachinskaya (Rus)22.38
3 Torri Edwards (US)22.47
4 Muriel Hurtis (Fra)22.59
5 Zhanna Block(Ukr)22.92
6 Beverly McDonald (Jam)22.95
7 Natalya Safronnikova (Blr)22.98
8 Anzhela Kravchenko (Ukr)23.00