Rubens Barrichello hopeful of improvements after poor IndyCar practice form at St Petersburg

The Brazilian struggled to recover after losing track time to a still-unidentified mechanical problem in the opening session, and said that his lack of familiarity with both the car and the nuances of the circuit made it hard for him to close the gap.

"I was going to play catch-up already just by learning the circuit," Barrichello said. "Then I did two laps, learned nothing on the track, and when you start the second session and other people have already made developments of the car ... I'm too far down.

"I'm not happy with the conditions of the car, and if I ask too much of myself learning the car and the track today, that equals walls. I'm below my target today by a long way just because my day was set up by a problem."

Barrichello could only manage a best time of 1m05.6681s in the morning, leaving him 2.6s adrift of the benchmark. He improved to post a 1m03.3290s in the afternoon, but was still left 1.3s short of Penske driver Will Power's best time.

Despite admitting that he'd fallen short of his own expectations on the first day, the KV Racing driver remains optimistic of getting up to speed.

"Like I said from the beginning, I need to keep my feet on the ground," he said. "I need to be on the track as much as I can to learn everything. The track is nice, but it is bumpy, and you need to learn [it] yourself, through bumpy braking, and some lines.

"Obviously I am OK with learning, but I am still far behind. I'm not happy driving the car just yet, and I'm not comfortable driving the car just yet. That loss of track time might hurt us a little bit more. I hope that we can improve a lot tomorrow and be happy-ish."