Graham Rahal set the top time on Friday with a 1:09.6031s in the #38 Service Central car just after the chequered flag came out at the end of the day's practice session ahead of Sunday's Honda Indy 200.
Rahal - who grew up less than 80 minutes away from the Mid-Ohio Sports Car Course in New Albany - was just 0.049s faster than EJ Viso who popped up into second place ahead of Dario Franchitti who had looked set to take the session honours until the final seconds. Franchitti was just ahead of road course king Will Power in fourth.
"It's such a fantastic track and has a lot of history with our family," said Rahal. "It feels good to start the weekend off this way for sure. I think we showed the grip is low, but at the end of the day it felt pretty good. I can't complain too much.
"I was satisfied that we didn't run a second set of tires. I know others around us did and we were still quickest. And that lap wasn't really a good one," he said. "I think Dario was struggling and he was dropping wheels left and right and I was following him. I missed some apexes, but to get the speed out of it feels pretty good."
Franchitti agreed that he was struggling for grip at this early stage. "The track wasn't in great shape and we spent the majority of the session struggling to get grip in the GE car," he said.
Two drivers having a less happy time were Marco Andretti and Takuma Sato, who spent most of the 75 minute session sidelined - the first 45 of which were reserved for rookies and those outside the top ten - in the pits.
"We're having some electrical problems with the car so we were only able to run five laps during practice," explained Marco. "There's a disconnect of some kind between the paddle shifters and the gearbox, so basically we can't really shift. It's a shame to miss basically an entire session."
Sato's problem was engine-related. "I had an installation lap and I had just started to run a couple of laps to warm-up the car. I immediately felt that the power was down and heard a noise." The KV Racing Technology-Lotus team pushed the #5 to the garage to replace the engine overnight.
There was a brief full course caution when Ryan Briscoe spun in turn 6 on the 2.258-mile, 13-turn circuit midway through the portion of the session open to all cars. A later spin by Sebastian Saavedra saw the #34 beached but dealt with under local waved yellows.
British driver Martin Plowman finished the session in 19th place with a lap of 1:11.1767s in his IndyCar series début.
Full times and positions