The race had been billed as a head to head showdown between Brownlee and London 2012 silver medallist Javier Gomez.
But it was South Africa's Richard Murray and Portugal's Joao Silva who claimed the silver and bronze as Brownlee jogged and walked up the finishing chute to record over a 20-second victory.
Brownlee set a blistering pace in the swim, but was not able to entice others to work with him to form a break away on the 40km bike. However, he set out on to the 10km run with intent and was never challenged, while British team-mate Adam Bowden finished sixth.
"I'm sure you think I'm lying when I said I've only done six weeks' training, but I'm not lying," he said.
"I did Abu Dhabi six weeks ago and I pushed on since then, that's all I've done in terms of really meaningful work on the track.
"I think it's good to have an injury-free winter. I enjoyed that, it was great."
Brownlee is planning his next race in Madrid as he seeks to arrive at London's Grand Final later this year in pole position for another world title.
Olympic bronze medallist Jonathan Brownlee, having missed San Diego, is expected to make his season debut next month in Yokohama.
- Sports & Recreation
- Jonathan Brownlee