Serpentine saved the bookmakers in the Derby (Bill Selwyn)So often the scourge of bookmakers, Aidan O’Brien was this time the hero for the layers after Serpentine upset the odds in the Investec Derby.

The 25-1 shot – one of six runners in the field for the Ballydoyle trainer – made all the running and won unchallenged in the hands of Emmet McNamara.

There was even each-way glee for the bookmakers, as Andrew Balding’s Khalifa Sat (50-1) and the winner’s stablemate Amhran Na Bhfiann (66-1) filled the places in the premier Classic at Epsom.

Yet just over an hour and a quarter earlier, O’Brien’s win with 11-10 favourite Love in the Oaks had the bookmakers on the ropes.

Nicola McGeady of Ladbrokes said: “As Derby results go, we couldn’t have asked for a better result. Despite coming from the Aidan O’Brien stable, he was far down the pecking order amongst punters. Results weren’t going our way today, especially with the favourite winning the Oaks, but this result has saved the day for us.”

Paddy Power spokesman Paul Binfield echoed that sentiment.

He said: “We were fearing the worst after Love easily justified favouritism in the Oaks, but Serpentine was a cracking result in the Derby and the placed horses were massively in the bookies’ favour as well. It’s been a good day for the books.”

Betway had not been as badly affected by Love’s triumph as they had been fearing victory for Frankie Dettori’s mount, Frankly Darling, who was only third.

Spokesperson Chad Yeomans said: “It wasn’t the Derby result that anyone was expecting, but you can never rule out Aidan O’Brien’s horses. Serpentine’s shock success wasn’t backed by many of the Betway punters and credit must be given to his rider Emmet McNamara for his enterprising ride.

“The first three races on the card were all good results for the Betway punters, but our fortunes changed in the Oaks, despite seeing a winning favourite. Frankie Dettori aboard Frankly Darling was well-backed and by far the worst result in the book, so Love’s victory in the fillies’ Classic was a good one and was welcomed on the trading room floor.

For Coral, the Derby was a good all-round result.

“After Love had run away with the Investec Oaks to the delight of favourite backers, we went into the day’s second Classic fearing a win for English King or Kameko, but neither of that pair, nor anything else, could get close to the front-running Serpentine,” said their spokesman David Stevens.

“His 25-1 victory ensured the biggest betting race of the Flat season very much went the way of the bookmakers, with the placed horses the icing on top our cake.”

For William Hill, it was probably their best-ever Derby result.

“Although we have not been able to confirm it yet, it looks like Serpentine is our best ever result in the long history of betting on the Derby,” said their spokesman Rupert Adams.