The Spanish Formula 1 driver completed Rookie Orientation Practice on Wednesday, clearing the way for him to participate in the race later this month.

Alonso completed 55 laps in the Dallara DW12 with a peak average speed of 219.654mph after what team boss Michael Andretti labelled a "perfect" run.

The two-time F1 champion said he now wanted to focus on getting a better feeling for the car, as he felt it was driving itself.

"It was fun," said Alonso. "I think it's a good way to start to build the speed. It was probably a little bit difficult at the beginning to reach the minimum, but in the next stages I felt good.

"Hopefully we can put some laps now and start feeling the car a little bit because at the moment the car is driving itself. I'm not driving the car."

He added: "We are already with 40 laps in my pocket so you are able to fine-tune the lines a little bit and up-shifts and down-shifts, which gear to use in which corner.

"At the moment everything looks good but now the real thing starts."

The McLaren driver praised the Andretti Autosport squad for being "amazingly helpful" during his first day of running at the IMS.

"So far it has been good. The team was amazingly helpful. Running alone is quite okay, but we'll see later over the next weeks," he said.