BEIJING — The U.S. men and women both dropped the baton in the Olympic 400-meter relays Thursday night and failed to advance out of the first round.

First, men's anchor Tyson Gay, part of the American team that won the relay at last year's world championships, did not get the red metal stick from third-leg runner Darvis Patton.

Then, about 25 minutes later, women's anchor Lauryn Williams flubbed her exchange with Torri Edwards, their baton dropping to the ground, too. At the 2004 Olympics, Williams started running too early and missed a handoff from Marion Jones in the final.

"If people want to assess the blame to me, that's OK. I mean, I can take whatever it is that people are going to dish out," Williams said. "We had good chemistry. The hand was back there. She was there. I don't know what happened."

Unlike the men, who stopped racing, Williams scrambled back on the wet track to pick up the baton and finish the lap. The United States, of course, was the last of eight teams in the heat to finish, in a time of 48.95 seconds. Belgium finished first in 42.92.

Jamaica, continuing its strong showing at the Bird's Nest, won the other preliminary women's heat in 42.24.

Earlier, when Gay reached back for his exchange, he never got a grasp of the baton, which tumbled.

Afterward, Gay and Patton both took the blame.

Gay, who also failed to reach the final in the individual 100, said he felt the baton and "then I went to grab it and there was nothing. It's kind of the way it's been happening to me this Olympics."

He said he never before dropped a baton in a relay and that he and Patton practiced all week without missing a handoff.

"That's Tyson Gay. He's a humble guy," Patton said. "But I know it's my job to get the guy the baton, and I didn't do that."

Trinidad and Tobago won the heat. Only four of the eight teams managed to make it all the way around the one-lap race without a problem in a light rain.

Jamaica won the second heat, with former 100 world record-holder Asafa Powell running the anchor leg. Usain Bolt, who broke the world records in the 100 and 200 while winning those gold medals, was given the night off but is expected to run in Friday's relay final.