Non Stanford was "overwhelmed" and "pretty shocked" by her
The 24-year-old Welsh competitor won by 26 seconds, with British team-mate Jodie Stimpson third.
She said: "I was pretty shocked to win by so much and to run away so early on the run."
But Stanford says the win is a confidence boost ahead of the European Championships in Alanya, Turkey on Friday, 14 June, 2013.
Her season has also included wins in the opening round of the 2013 French Grand Prix series in Dunkirk, and the European Cup in Portugal.
Jonny Brownlee completed a British double by winning Sunday's men's race.
And with Stimpson, 24, joining her on the podium and Wales' 2009 and World series winner Helen Jenkins expected to return to the fray in 2014, Stanford says British triathlon is in good health.
"It was fantastic overall for GB [in Madrid]," said Stanford.
"Jonny obviously won the guy's [race] in incredible fashion. He was absolutely phenomenal, then we had me and Jodie on the podium.
"I think that's the first time we've ever had two British girls on the world series podium at the same time.
"So fantastic really and it shows even though Helen's not racing with us this year, [there's] still strength in depth."
She says the 1,500m swim in Madrid was possibly the toughest she has experienced, dubbing it "really physical".
"Some of our coaches were stood at the first buoy and said I got a pretty hard time going around it - they saw me go under quite a few times," said Stanford.
"But it's part and parcel of the game and I managed to recover from it so I'm pretty pleased with that.
"Winning a world series event will give me a lot of confidence going forward and yes, definitely going into the Europeans it will be a big boost."
After the event in Turkey Stanford will prepare for the world series' fifth round in Kitzbühel, Austria on Saturday, 6 July.