Britain's Rebecca Adlington saw Camille Muffat of France take her Olympic 400m freestyle crown but came through late on to secure a hard-earned bronze as American Allison Schmitt took silver.
"We said if she was there or thereabouts, she was the person for the closing stages. That is her strength. Give her an opportunity and she will take it. A fantastic performance from Rebecca, what a gutsy swim. The crowd love it."
Adlington's swim gave Great Britain their first medal in the pool and represented a fine return in the weaker of her two events against a fearsome field.
At the halfway mark she was down in sixth but charged through over the last 100m to edge out Lotte Friis of Denmark and Italy's world record holder Federica Pellegrini.
Muffat led Schmitt from the first turn and touched in a new Olympic record of four minutes 01.45 secs, with the American 0.32 secs down and
third in 4:03.01.
That time for the Briton was faster, in a textile swimsuit, than the time she produced in the now-outlawed fast suit when taking gold in Beijing.
The improvement, allied to
record and Pellegrini's finishing position, underlines that this was a medal won rather than a title lost, although the 23-year-old had swum faster at the British Trials in March.
"After this morning, I didn't know what to expect, only qualifying in eighth. Tonight there was no pressure on me at all," Adlington told BBC Sport.
"I know everyone else wanted to say, 'Oh, you got the gold in Beijing' but to me I was not expecting that at all, so I am so so pleased.
"I would have liked to go a tiny little bit faster and kind of equal what I did in March, but to be honest - with the whole environment and the event - that kinds of adds stuff and you forget that all that is a toll on you, and the emotion can take it out of you a little bit."
Four years ago, Adlington used her 800m endurance to close down her rivals in the last 50m and snatch that shock gold.
"Applause to Becky Adlington. She was under the pump, with so much pressure to perform and talk of her not even winning a medal. What I was so impressed with was she took it out to put herself through the most pain possible to win that medal. She is a stronger 800m swimmer and, based on that display, we can have a bit more confidence in her now for [the longer] race."
Here in London the task was made harder by her comparatively slow time in winning her morning heat, which meant she began the final out in lane eight.
With ear-splitting support from the partisan home crowd she made light of that draw and began to claw her way past Pellegrini in lane one, Coralie Balmy in three and Friis in two.
Muffat and Schmitt were clear and away in the middle two lanes but Adlington began to tick off her other rivals - from sixth to fifth between 200m and 250m, up to fourth at 300m and then through past a tiring Balmy on the final turn.
"The crowd was so overwhelming. Twelve years' hard work has gone into that," Adlington added. "Four hundred metres always feel so hard for me and they were so far ahead. I'm so glad I've got a medal at a home Games. Not many people can say that."
Adlington, who is the first British woman to win swimming medals at successive Olympic Games, begins her quest to defend her 800m freestyle title in the heats on Thursday, with the final on Friday evening.