The early pace on Saturday was set by Kamui Kobayashi with 1:21.242, but Alonso supplanted him at the top of the times mid-morning when he dipped down to a 1:21.140 after 30 laps of running.
Brickyard Crossing, which used to host a Senior PGA event, is truly one-of-a-kind: four holes play inside the infield of the oval track, often with loud cars running by on test laps, linked by a tunnel to the fourteen holes just outside the stadium.
" He added: "When we finally did some running we put in a few laps of wet set-up but with the track changing so much it is always hard to draw too many conclusions.
Toro Rosso's Sebastien Bourdais was classified seventh on an impressive debut following Barrichello's exclusion, despite retiring with engine failure while running fourth ahead of Alonso and Kovalainen with three laps to go.
As such, though Trulli's Toyota running on 'softs' meant he was faster than Vettel in the final 16 laps of the race and had the Italian right behind his rival, he could not pass the Red Bulls's Chinese GP winner who managed to hang on for second place.