LONDON -- The United States and Jamaica reached the final in the women's 4x100-meter Olympic relay Thursday night.
The Americans easily won their heat in 41.64 seconds, with Tianna Madison, Jeneba Tarmoh, Bianca Knight and Lauryn Williams carrying the baton.
The Jamaicans weren't nearly as smooth. Sherone Simpson and Schillonie Calvert nearly botched the exchange between the second and third legs. With Samantha Henry-Robinson running the opening 100 meters and Kerron Stewart serving as the anchor, the Jamaicans finished in 42.37 seconds, edged at the line by Ukraine.
The final is Friday.
Both high-profile teams failed to medal in Beijing in 2008, the Americans faltering in the prelims and the Jamaicans botching a handoff in the final. It was the lone sprint the Jamaicans didn't win in China. The U.S. also failed to medal in Athens in 2004.
The sqauds could look drastically different for the final, since 100-meter finalists Shelly-Ann Fraser-Pryce of Jamaica (gold), Carmelita Jeter of the U.S. (silver), Veronica Campbell-Brown of Jamaica (bronze) and 200-meter champion Allyson Felix (fifth in the 100) are all expected to be subbed into their respective teams.
Felix and Tarmoh finished in a dead heat for third in the 100 meters at the U.S. trials in late June. Tarmoh eventually gave up her spot in Olympic field, avoiding a runoff.