The Olympic Champion fought off stiff competition from Mhairi Spence (GBR) who won silver and Anastaysia Prokopenko (BLR) broke the world shooting record to come from 18th place to win bronze.
Schoneborn, the Olympic Champion, and World #1 who is making winning World Cups a habit stated: "I am very relieved that I got through the first competition of the year.
I love coming to the USA, so I am excited to win this medal in front of the American crowd. I had a hard winter training in Colorado Springs which certainly helped.
Winning the fence set me up great for the rest of the day and I rode that momentum. Mhairi pushed me hard in the run, my quick last shoot made all the difference."
Spence, who matched her silver medal performance from World Cup #1 last year said: "I am really happy and overwhelmed, I had a good day and it was nice to finish well and kept it all together. In 2011 I had a break through year, but I knew I could improve, so I went away in the off season and worked on a lot of little things and it has paid off."
The pocket rocket from Belarus, Prokopenko broke 2 world records on her way to the bronze medal. The mother of one shot her final 5 shots in 9.3 seconds to break the single shoot world record and shot her 15 shots in a staggering 30.4 seconds to be the fastest Pentathlon shooter (men or women) on the planet. "I can't believe I shot that fast" said the Belarusian who recovered from a disappointing 33rd in the swim to win the bronze. "At the start of the combined event I thought I had no chance, I was very relaxed and just shot and ran and thankfully it worked."
The surprise of the event was Chloe Esposito (AUS) who finished 5th which is a fantastic achievement in only her 5th World Cup. "I am in shock" said the Oceanian Champion. "I have trained extremely hard, but never thought I would finish this high. I now want to keep this up until the London Olympics."
World #3 Laura Asadauskaite (LTU) grabbed 4th and the British pair of Samantha Murray and Heather Fell finished 6th and 7th respectively to cap off a brilliant day for Great Britain.
All these athletes now head down to Rio de Janeiro for World Cup #2 next week, but before that is the Men's Final tomorrow. Follow all the live results on Pentathlon.org.