BEIJING — Another American boxer wins, and another bows out with a health scare. Although the U.S. team isn't the world's most consistent bunch, it's been consistently dramatic in the Olympics so far.

Welterweight favorite Demetrius Andrade won a brawling Olympic debut Sunday night, but light welterweight Javier Molina lost a one-sided decision to Bulgaria's Boris Georgiev at Workers' Gymnasium.

Moments after the 18-year-old Molina was eliminated by his veteran opponent, U.S. coach Dan Campbell revealed the youngest American boxer wasn't cleared to fight until late Saturday after doctors discovered a hole in his lung had leaked air into his body.

"You know, it's just been one thing after another," Campbell said.

Molina developed a throat infection earlier in the week, but still wanted to walk in Friday's opening ceremonies. After the Los Angeles-area native complained of pain the next morning, a chest X-ray revealed tiny pockets of air in Molina's right shoulder and neck.

"That usually signifies an air leak from the lungs," said Bill Kuprevich, the American team doctor. "It's fairly common — sometimes happens with infection, sometimes happens with trauma. To him, it happened between resting and walking in the opening ceremonies."

Though Molina's condition sounds frightening, it wasn't caused by boxing and should heal on its own. But it was yet another obstacle for a team that's already gone through the drama of Luis Yanez's banishment and reinstatement to the team before Beijing, followed by bantamweight Gary Russell Jr.'s collapse Friday in a failed attempt to make weight.

"I felt like I couldn't get comfortable in there," Molina said. "I felt kind of sluggish all night. I knew what I had to do, and I just didn't do it. I just wasn't feeling comfortable."

Molina shaved his hair into a mohawk before the bout, but not even teammate Shawn Estrada's barbering skills could help him with Georgiev, who beat American Rock Allen on the way to a bronze medal in Athens. Georgiev toyed with Molina, winning every round in a 14-1 decision.

"I think what we saw was a young man in there with a grown man," Campbell said.

Andrade also had to be the bigger man in his 11-9 victory over Kakhaber Jvania of Georgia, who charged, pushed and shoved the Rhode Island native all night. Andrade got few chances to show off his peerless reflexes, but kept his composure with just enough counterpunching, including the clinching point on a whip-quick left hand in the final seconds.

"I fought him in the world championships, and he did the exact same thing," said Andrade, who thought the judges missed several of his fast scoring punches. "It was a rough fight. Nobody in there wants to box me, so I guess I'm going to have to slug it out, bang out the body shots and then go back to boxing."

Andrade said he was buoyed by loud cheers from the crowd.

"It felt good," Andrade said. "That gave me a boost to keep on going, even though I knew the score wasn't fair."

The rest of Sunday's session was highlighted by two outstanding performances by unrelated British fighters named Saunders.

Billy Joe Saunders, the 18-year-old welterweight from a Gypsy family, beat Adem Kilicci of Turkey 14-3, while light welterweight Bradley Saunders stopped Samuel Neequaye of Kenya midway through the first round with two knockdowns.

In his first major international tournament, Billy Joe Saunders was every bit as exciting as promised while battering Kilicci, who won a bronze medal at last year's world championships in Chicago.

Saunders' ring flair is bound to draw comparisons to Amir Khan, the teenage lightweight who catapulted to stardom and sparked an English boxing revival with a surprising silver medal in Athens.

"I think that was a mature performance from a man who isn't 19 yet, and against a world bronze medalist," coach Terry Edwards said. "He showed tremendous maturity. Billy is a bit more mature (than Khan), to be honest with you."

Light welterweight contenders Gennady Kovalev of Russia and Roniel Iglesias of Cuba also opened competition with easy wins. Several hours before welterweight Russian teammate Andrey Balanov struggled to a victory, Kovalev beat China's Maimaitituersun Qiong 15-8 in the day's first bout, disappointing the home crowd.

The fans were thrilled later by welterweight Hanati Silamu's impressive 21-4 win over Precious Makina of Zambia, putting two fighters on the inexperienced Chinese team through to the second round even before light flyweight favorite Zou Shiming's first bout.