The 23-year-old from Leeds, who was also winning this race for the second year in a row, led almost from start to finish in the Spanish capital.
He was in the lead group out of the water, led a breakaway group in the bike leg of the race and never looked back as he completed the race in one hour 50 minutes and 42 seconds.
"It's a good triathlon course this one, as I keep saying it's a pure triathlon course," Brownlee told triathlon.org, the official site of the International Triathlon Union.
"Our group was incredible there, all the other riders did turns throughout the race and it was a fair race I think, so I enjoyed it but it was tough, it's always tough."
Javier Gomez finished second on home soil to claim the lead in the overall 2013 series standings, while Russia's Ivan Vasiliev was third.
Brownlee's brother Alistair - the reigning Olympic champion - missed Sunday's race because of an ankle injury.