?Bolt beats Gatlin, takes 200 meters.

Usian Bolt won his second duel against American Justin Gatlin at Beijing athletics world championships on Thursday as the Jamaican "Lightening" stormed to defend the 200m title, winning every world and Olympic individual title he actually ran in the past seven years.

Bolt edged ahead into the straight and romped home in a time of the year's best time of 19.55 seconds, beating arch rival Gatlin again and the American's previous world leading time of 19.57.

"I am just happy. I told you guys taht I will do it. There was no doubts," said Bolt whose appearance in Beijing even was in doubt months before the world championships.

The 29-year-old, who celebrated his birthday in Beijing last Friday, seemed on way back to his best shape after struggling for the season to run sub-20. By now, Bolt has clinched 11 world and Olympic individual gold medals, just missing the 100m title in 2011 Daegu worlds due to a false start.

"I was not ready to focus on time. I knew I was not in the shape for a world record. When it comes to the 200m, I am a different person, I was beaten there only once. My four world championships gold medals in the 200m. This is a big deal, a great accomplishment."

Gatlin, who finished second to Bolt in the 100m final on Sunday, took silver in 19.74. Anaso Jobodwana of South Africa in 19.87

Gatlin, 33, was proud of his silver medal and is ambitious for next year's Rio Olympic Games.

"I'm the oldest man in the field and still running, running pretty well. It feels good to go against this guy (Bolt) right here. I'm just going to prepare myself for next year, for the Olympics and come out even stronger," said Gatlin, who is in stunning form this season and not yet losing once since the 2013 world championships, winning all 22 races.

Bolt and Gatlin may have a round three clash in the 4x100m relay and the Jamaican was confident of his team's victory no matter he runs the relay or not.

"I am not sure about the formation of our relay team. There will be a meeting tomorrow and we will decide about it. In the World Relays when Jamaica was beaten by the US, Justin Gatlin had a big game in their victory. I guess he will be tired now. There will be no reason why we should not win the relay," he said.

World record had been expected in women's hammer throw when London Olympics runner-up Wlodarczyk held a firm lead in her third attempt with 80.27 meters, which broke the championships record of 78.80m set by Tatyana Beloborodova in Moscow two years ago. She improved to 80.85 in her fourth throw and clinched her second world title.

The 30-year-old is in incredible form this season. On August 1, Wlodarczyk became the first woman to break the 80-meter barrier, tossing the hammer out to 81.08m to break her world record.

Beijing Olympic bronze medalist Zhang Wenxiu created her best result at the top world competitions, winning a silver after the 29-year-old threw the hammer to in 76.33 in her fourth attempt.

"The Bird's Nest is my lucky place," said Zhang. "I am very happy with my silver today but it did not come easy to me. I got a season's best, that is great."

French Alexandra Tavernier bagged a bronze in 74.02.

In the men's triple jump, the world record of 18.29 set by Britain's Jonathan Edwards in 1995 world championships looked within reach for the two 20-something men - London Olympic champion Christian Taylor of the United States and former junior world champion and Moscow runner-up Pedro Pichardo of Cuba.

Taylor won at the end, creating this year's world leading result of 18.21 meters in his last jump while Pichardo had to settle for second place in 17.73. Beijing Olympics champion Nelson Evora from Portugal, 31, took bronze in 17.52.

In the women's 400m, world and Olympic 200 meters winner Allyson Felix of the United States fended off challenges from younger opponents to be crowned in 49.26 for the first time in this event at a world championships.

Former world youth champion Shaunae Miller from Bahamas, nine years junior to Felix, was second in 49.76 before Jamaican Shericka Jackson, also born in 1994, came third in 49.99.

Kenya stands atop the medals tally with six gold, three silver and two bronze. The United States rose to second with three gold, two from Thursday, and four silver as well as five bronze. Jamaica is third with three gold. Host China sits 15th with three silver and one bronze.