Caturra came from the clouds to claim top honours in the Wainwright Flying Childers Stakes at Doncaster.
Successful in a novice event at Bath and the Listed Rose Bowl at Newbury earlier in the season, Clive Cox's juvenile was last seen filling the runner-up spot behind the re-opposing Attagirl at York.
The son of Mehmas was a 7-1 shot for this Group Two assignment, with much of the pre-race attention focusing on the Richard Hannon-trained Armor - who was dropping in distance and class after finishing fourth in the Prix Morny.
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The market leader looked slightly outpaced at halfway, but picked up well in the final furlong to grab the lead under Ryan Moore.
Unfortunately for favourite backers, however, Caturra came from even further back in the hands of Adam Kirby - displaying a brilliant finishing kick to get up and beat Armor by a neck.
Cox said: "I wish I wasn't stood at the furlong pole - I wish I had been closer to the line as I was a bit worried when he passed me. I didn't think he was going to get there, but he's always shown us a pleasing turn of foot.
"I've never had a sprinter with such a sober approach. He had a lay down at the races when he arrived here today.
"He's got a wonderful mind and lot of speed. We just had to fine-tune how we were riding him as he was using up a little bit too much too early.
"That was fantastic and brilliant Adam (Kirby) got there."
The Lambourn handler raised the possibility of Caturra returning to six furlongs at some stage, adding: "He does get six and ridden this way, he's switching off so well in his races we can think about that as well.
"I don't think there's any doubt he's done it really well today. Also, he's coped with softer ground last time than I thought possible.
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"He showed more of a versatile approach than we imagined, so I'm really pleased.
"His turn of foot was amazing and to do that over five is very special. From a management point of view, his laid-back temperament is a big asset."