In a close-run contest that kept jurors locked away for 15 hours on the final judging day, Madrid-based agency Shackleton eventually triumphed with "Lopetegui Deposit" for Banco Gallego.
It outrun two other hot contenders: Springer & Jacoby, Hamburg's "Shark" campaign for Olympus Imaging Europa and "Verb Yellowball", a youth fitness drive for the Centers for Disease Control and Prevention from Arc Worldwide, Chicago.
"We had three equally worthy winners of the Grand Prix," said Rory Sutherland, vice-chairman of Ogilvy Group UK and the Direct Lions jury president. In the end, Shackleton's won "on the degree of difficulty involved", despite not being the most beautifully crafted.
"It was a masterpiece of opportunism, based on a freak incident. Branding a product around a celebrity in the outstandingly conservative category of financial services is the most remarkable piece of creative thinking," he said.
More bronze Lions than usual - 40 in total - were awarded this year, and fewer golds and silvers, reflecting a general rise in direct marketing standards, Sutherland said. "Things that didn't make the shortlist this year would have been award winners ten years ago," he pointed out.
Sutherland's own agency was the most successful of the UK contingent, scooping a gold, two silvers and a bronze for its Department of Health/Cancer Research UK "Smoke is Poison" campaign. Harrison Troughton Wunderman won three bronzes and RMG Connect one.
Among the judges who rooted for Springer & Jacoby's "Shark" was Dave Woods, executive creative director at Claydon Heeley. "It's sexy and sexy is what the direct industry needs," he said.
Banco Gallego's Grand Prix work took advantage of footage of Barcelona goalkeeper-turned-sports presenter Lopetegui fainting on Spanish TV which was spread virally and downloaded a reported 700,000 times. Shackleton reworked the film to show the reason for his collapse: he had seen a board displaying the bank's new interest rate. That film was then seeded virally to market a new product named after the ex-footballer and offering that interest rate.