SYDNEY, Australia (AP) -- U.S. boxers don't seem satisfied with just winning their Olympic bouts. Now they're starting to dominate them.

 Jeff Lacy and Ricardo Juarez showed Monday why medal expectations are so high among American boxers with a pair of spectacular wins that kept the U.S. team undefeated through six Olympic fights.

 Juarez pitched a shutout, while Lacy nearly knocked his opponent out of the ring with some thundering punches in an impressive display that underscored the strength of the American team after three days of competition.

 "I was trying to strike some fear in those middleweight minds," Lacy said. "I'm pretty sure I'm the hardest puncher on the U.S. team."

 Actually, Lacy is, at least according to a computerized heavy bag that U.S. team officials used to measure punch strength in training.

 A different type of measure was used Monday. It was the body and head of Brazil's Cleiton Conceicao, both of whom took a beating before the fight was finally stopped with 1:02 left in the third round.

 Lacy won the 165-pound fight by the 15-point rule, 17-2. But he might well have knocked Conceicao out had the fight gone any further.

 "I sensed that he was a little bit afraid of me," Lacy said. "I came here with one thing on my mind -- bring the gold back to St. Petersburg, Fla."

 To do so, Lacy will have to get past Cuba's Jorge Gutierrez, who won his opening fight 20-11 against Somchai Cimlum of Thailand. And Juarez has both 1996 gold medalist Somluck Kamsing of Thailand and Yosvany Aguilera of Cuba on his end of a tough 125-pound bracket.

 Both Kamsing and Aguilera won easily -- by identical 17-2 scores in the third round -- on Monday, with Kamsing enjoying the backing of a large and noisy group of his countrymen. Aguilera's win kept the Cuban team undefeated at 5-0, all on easy wins.

 But that's a familiar tale for most of the 12 U.S. boxers, who came into these games fully aware of the Cuban boxing mystique that accounted for four gold medals and two silver in Atlanta.

 "There's not a doubt in my mind that we're going to be here all the way," Lacy said. "This is a bunch of good guys. We've all come together as one."

 Even coach Tom Mustin was impressed after watching Juarez stop Iran's Bijan Batmani 15-0 in the third round and then going right back out a few fights later to see a thundering punching display by Lacy.

 "I thought we'd have a pretty good team, but I wasn't sure how good," Mustin said. "These guys are only thinking gold. That's all they've got in their mind."

 Not entirely, at least in the case of Juarez.

 The 19-year-old who won a world championship last year at 125 pounds said listening to a sports psychologist with the U.S. team has helped him focus on the moment in the ring and not think about what future fights might bring.

 He certainly looked focused against Batmani, who took a battering from the second round on before a right uppercut gave Juarez the final point he needed to win by the 15-point rule with 1:08 left in the third round.

 "I always knew what I was doing in the ring, but he has helped me stay focused by thinking of how I am at my best," Juarez said. "More advice certainly won't hurt me."

 Juarez, whose father gave him the middle name Rocky in honor of Rocky Marciano, said winning the world championship in his hometown of Houston gave him a reputation in his division but no more pressure to win a medal than any of his teammates.

 Still, he admitted to a case of jitters as he waited to get into the ring for his first fight.

 "Nervous, very nervous," Juarez said. "These are the biggest fights of my life."

 Six Americans still have to make their Olympic debuts, including heavyweight Michael Bennett and super heavyweight Calvin Brock. But the team's quick start had Mustin smiling even as he carefully balanced the ever-present toothpick in his mouth.

 "We've got a great beginning and we're just trying to keep rolling," he said. "Nobody wants to be the first to lose. So they're going to fight their hearts out not to lose."