The American superstar won the title for the first time, without ever finding the form that has made her one of the all-time great women sprinters.

Jones won in a time of 22.39secs, with Debbie Ferguson of the Bahamas second in 22.52 and another American, Kelli White, securing bronze with 22.56.

Her defeat to Ukraine's Zhanna Pintusevich-Block in the 100m on Monday ranks as one of the great upsets in the sport in recent years.

She led from the front and ran a great bend - only to come under pressure from Ferguson as she tired in the closing stages.

But Jones held on in the final metres to win with a stride to spare in front of the biggest crowd at the championships.

"It was rough for me earlier in the week but the crowd really got behind me," a relieved Jones told BBC TV.

"It was wonderful - it seemed like everyone in this stadium was cheering for me.

"I knew I had to put it together in the early stages, because I didn't know how long I could hold on for.

"I could feel Debbie coming (near the finish) and I was getting tired. But I ran a strong curve.

"Before the race I was very emotional. I really wanted this."