The U.S. was hoping for big-time performances from its two best boxers at the women's world championships.
And that's exactly what the Americans got.
"It really hasn't hit me yet," Esparza said. "But I'm so happy."
The teenaged Shields -- who won gold at the 2012 London Games -- finished an impressive week with a unanimous decision over China's Qian Li in the middleweight division. She was named outstanding boxer of the tournament.
Esparza had a tougher bout, taking a split decision over Lisa Jane Whiteside of England to add a world title to her Olympic bronze from two years ago.
“I think my experience really played a big role in this tournament," the flyweight said. "My nerves have impacted me in the past but because I’ve been here so many times before, it wasn’t as nerve-racking."
Tiara Brown added a bronze medal for the U.S.