Ron Siler had just taken a beating, and now it seemed like the whole U.S. team was down for the count. Fighters weren't following directions, medal hopes were slipping away and some of the performances had been downright embarrassing.

Then Andre Dirrell put on a show to remind everyone that not all was lost just yet.

With a dazzling display of speed and power, the American middleweight dominated Nabil Kassel, his Algerian opponent, before the fight was stopped after two rounds. More importantly, perhaps, Dirrell also gave hope to the remaining fighters on the U.S. team by advancing to the quarterfinals.

"He knew there was a sense of urgency," U.S. Coach Basheer Abdullah said. "He knew we needed this bout, and he came out and performed."

Meantime, Najah Ali, who gained renown as the flag-bearer for Iraq's reconstituted Olympic team and as the Games' smallest boxer, lost his second-round light flyweight bout to Armenia's Aleksan Nalbandyan.

The crowd embraced the 106-pound fighter's effort, chanting "Ali! Ali!" in the fourth round. When the fight ended, Ali was lifted off the mat in a bear hug by Maurice "Termite" Watkins, his American coach.

"He fought a fantastic fight," Watkins said. "We did this in 10 months, and they've all been getting ready for this for four years. I think of him like my son. I love him very much."

U.S. middleweight Andre Dirrell lands a left on Algeria's Nabil Kassel.