The British Gas ITC Loughborough swimmer, who finished fifth in the 10km at London 2012 last year, put in a determined swim to lead the race out and hold off a number of challenges to his lead in the final 2km of the race.
Fogg eventually won the race in 1:56:38.10 ahead of Germany's Olympic silver medallist Thomas Lurz (1:56:40.20) and Italy's Simone Ruffini (1:56:40.40).
Tom Allen (British Gas ITC Swansea) and Tom Sunter (City of Sheffield) also put in competitive performances amongst a world class field of 65 swimmers, finishing 11th (1:56:54.80) and 28th (1:59:41.50) respectively.
Meanwhile, 16-year old Lucinda Campbell (Windsor) showed promise in the women's event, heading out with the pack before ultimately finishing 34th out of 50 in 2:17:53.40.
Berni Dietzig, Interim Head of Open Water said: "The boys have done a great job to achieve this result and the race was very challenging.
"The currents were extremely strong and consequently only those swimmers with the best lines and tactics had a chance of finishing in the top places.
"Due to clever tactical manoeuvres, Dan managed to swim at the front of the pack and escaped the mayhem 65 swimmers create when trying to get around a buoy at the same time.
"He was continuously challenged for the lead by some of the world's best open water swimmers over the last 2km, but he displayed his strength and determination and defended his position into the finish."
Fogg's coach at Loughborough, Kevin Renshaw, added: "2012 showed Daniel that he really is an elite distance swimmer.
"This year he has worked extremely hard and raised his training to a new level. He is producing work that is better than any swimmer I have ever worked with and he deserves this result: it's a good step in our cycle towards Rio."