Double Olympic champion Rebecca Adlington squeezed past Jazmin Carlin to win the 200m freestyle at the British Swimming Championships.
It was Adlington's second title in Manchester, following the 22-year-old's 400m freestyle victory on Saturday.
Adlington was fourth at the final turn but burst through to touch home in one minute 58.90 seconds, 0.13 secs ahead of Carlin in a thrilling finish.
Keri-Anne Payne was third, with Rebecca Turner fourth and Jo Jackson fifth.
It was one of the closest races of the championships, with Payne leading until the halfway stage and then Jackson bursting ahead with 50m left. But Adlington timed her race to perfection and powered through with only 25m remaining.
Adlington described her victory as a "fight", saying: "I knew it was going to be a close race.
"The time isn't massively quick compared to the rest of the world.
Rebecca Adlington celebrates gold with Carlin (left) and Payne (right)
"This time of year it's about the racing and getting involved and that is what I have done this week and I am so pleased."
Carin's time was not quick enough to qualify for the individual race at the World Championships in Shanghai, but the Commonwealth silver medallist has already made the team in the 400m freestyle, where she also finished second behind Adlington.
The top four qualify for the 4x200m relay at the World Championships in Shanghai, although Jackson, a former 400m freestyle world record holder, will have to wait to learn if she will be selected for one of the two reserve places.
"That felt good to win in what was a packed, world class field and it just shows how strong our 4x200m relay can be," added Adlington.
"To get six girls all under two minutes is a great achievement. That's my second title of the British Championships and I still have the 800m to go so this week has been very good for me so far."
Michael Rock and Joe Roebuck both qualified for Shanghai after the duo battled it out in the 200m butterfly, with Rock the eventual winner of what was a tense tussle until the final 50m.
"That was the aim, to come here and make sure I qualify for Shanghai," said Rock. "The time was not where I want to be but I've moved on from last year.
"I've been working on my last 50m throughout the winter months and it felt good to give me the victory. I wasn't entirely happy with my performances in 2010 but that swim gets this year off to a good start."
Tom Allen led from the start to win gold in the men's 800m freestyle in 8:00.25, while East Kilbride's Douglas Scott clinched gold in the 50m breaststroke in 28.74 secs.
Meanwhile, defending champion Adam Brown qualified fastest for Wednesday's 100m freestyle after powering through in the latter stages to finish in 49.72 secs.
Grant Turner was second fastest with 100m backstroke champion Liam Tancock third.
Commonwealth bronze medallist Georgia Davies qualified fastest for the 50m backstroke, an event which will not feature 100m champion Gemma Spofforth and European 200m champion Lizzie Simmonds after both chose not to compete.
In the 200m butterfly, Ellen Gandy qualified in top spot in a time of 2:07.76 ahead of second-placed Jemma Lowe.
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