Phyllis Francis runs in a women's 4x400-meter relay heat at Olympic Stadium (AP Photo/David J. Phillip)

RIO DE JANEIRO (AP) -- The American women blazed through the opening heat of the 4x400 relay, then played it coy on what their lineup will be in Saturday night's final. 

Courtney Okolo, Taylor Ellis-Watson, Francena McCorory and Phyllis Francis won their heat and easily advanced to the final. After the race, the women were asked if teammate  Allyson Felix will run the final. 

"We don't know yet. I'm just going to leave you guys in suspense on that one," said Francis. 

Problem with Francis playing it coy? Felix has already said she's running in the relay. 

Felix won silver in the 400 meters in these games.