The Italian delighted local fans in Rome's Foro Italico as she secured gold with a convincing victory in a world record time of 3min 59.15sec, making her the first time a woman has been under four minutes.

 

 

Having hit the front at the 50m mark, Pellegrini controlled the race and finished more than a second clear of her British rivals with Jackson touching in 4:00.60 and Adlington 4:00.79.

 

Pellegrini said: "I knew I would finish first because I didn't see anyone else around me, but I didn't know about the record until I turned around and looked at the board.

 

Jackson, who had finished third at the Olympics in Beijing last year, finished a distant 1.45 seconds behind, and the gold medalist at last year's Games, Adlington, was third, 1.64 back.

Pellegrini led from start to finish, and the two Britons weren't even in striking distance for the second half of the race, with the cheers growing louder after each lap.

 

Jackson said: “It seemed like the whole of italy was out there tonight cheering on Federica and it pushed us all to the finish.

“To see those kinds of crowds watching that type of amazing racing is what it’s all about.

“It helps when there's two of us in a race like that but Federica was in a class of her own tonight.

“I'm so proud of what Becky and I achieved tonight.

 

"For me it’s a place better than Beijing and I'm really happy with that.”
 

 Adlington said: "We've got PBs (personal bests).

 

"It's a very different environment, getting used to the heat.

 

"Obviously on home ground [Pellegrini] has got all that crowd cheering for her.

 

"It's definitely her night.

 

"It's definitely something I'm going to remember for the rest of my life.

 

"And in London [at the 2012 Olympics] that will be our crowd."

 

Adlington has stuck with her Speedo LZR swimsuit, while Pellegrini and the other competitors used 100 percent polyurethane suits from Jaked and Arena -- considered the fastest in the pool this year.

 

The Mansfield swimmers said: "I've proven that you can still get a medal."

 

Pellegrini won the 200m freestyle in Beijing but finished fifth in the 400m, despite entering as the world record holder.

 

She said: "This medal is worth a lot.

 

"It's more emotional than Beijing because it was tougher.

 

"This race was tougher mentally than physically.

 

"Only me and [coach Alberto] Castagnetti know how hard we worked this year.

 

"But sometimes mental fatigue can betray you.

 

"You can train all year but then if you're not 100 per cent in you're head, you don't win.

 

"I had some problems this year but my character helped me win, even if I didn't believe it until the last five metres."

 

At one race earlier this year, Pellegrini had to step off the starting block when she was overcome by a nervous breakdown.

 

And few hours before this final, she was not even sure she could race.

 

Pellegrini said: "At one point, I thought there was no hope.

 

"This afternoon I was in bed and I thought I had a fever, but I didn't want to measure it.

 

"In warmup, the cold water helped me cool down."

 

It was one of six world records to fall due in no small part to the controversial high-tech swimsuits which are set to be banned by the start of 2010.

 

Paul Biedermann also eclipsed Ian Thorpe's final world record as he took just 0.01 seconds off the Australian's mark for the men's 400m freestyle.

 

The German produced a blistering final 50 metres to overhaul Oussama Mellouli and posted a time of 3:40.07  to consign the Thorpe's seven-year world record to the history books.

 

Swedish teenager Sarah Sjostrom had broken the championship record in the very first event of the day and returned to set a scorching time of 56.44 in the 100m butterfly, 0.17 inside Inge De Bruin's world record from the Sydney Olympics nine years ago.

 

Ariana Kukors then smashed the 200m individual medley world record, the American leading from start to finish to take 1.42 seconds off Stephanie Rice's previous mark, touching in 2:07.03.

 

Germany's Britta Steffen lowered her own world record in the 100 metres freestyle to 52.22 seconds as she swam the lead-off leg in the 4x100 metres relay, although it was the Netherlands who triumphed in a new world record of 3:31.72 seconds.

 

World record holder Rafael Munoz managed a new championship 50m butterfly time of 22.68 seconds, while the American freestyle quartet, including Michael Phelps, set a championship mark en-route to victory.