Ferrari's Alonso fastest in 1st practice at US Grand Prix

Pit crews push Ferrari driver Fernando Alonso of Spain's car to their garage before the first practice session for the Formula One U.S. Grand Prix auto race at the Circuit of the Americas, Friday, Nov. 15, 2013, in Austin, Texas. (AP Photo/Darron Cummings) (The Associated Press)

Pit crews push Ferrari driver Fernando Alonso of Spain's car to their garage before the first practice session for the Formula One U.S. Grand Prix auto race at the Circuit of the Americas, Friday, Nov. 15, 2013, in Austin, Texas. (AP Photo/Darron Cummings) (The Associated Press)

Ferrari's Fernando Alonso posted the fastest time in the first practice session at U.S. Grand Prix, followed closely by Red Bull's Mark Webber in a session first delayed by fog and then interrupted and shortened because the medical helicopter was late to arrive.

Alonso drove the Circuit of the Americas in 1 minute, 38.343 seconds. That was 0.0028 seconds faster than Webber, who has just two races left in his Formula One career.

Red Bull's Sebastian Vettel, who is chasing a record eighth consecutive victory in a single season, was 18th at 1:40.662.

Fog delayed the start by 40 minutes. The drivers were on the course for only about 15 minutes before the session was stopped until the helicopter arrived. The initial 90-minute session was condensed into about 45 minutes.