The 2021 NASCAR Cup champion will make his IndyCar debut in May's blue ribband with Arrow McLaren, in partnership with Hendrick Motorsports, and completed 172 laps of Phoenix Raceway on Monday.
The test was moved up by a day due to the impending threat of rain, which forced Larson to “get my mind right to prepare myself for that”.
“I thought it went smooth,” Larson said after completing “three or four hours” of running.
“It was good to run through some things, get comfortable out there making laps, but get to do some pitstop stuff.”
Larson revealed that on his final run of the day, “I almost spun out“ when he began searching for the limit but fortunately “was able to catch it”.
“Just got caught off guard a little bit,” Larson said. “I had some warnings a few laps before.
“Honestly, though, nothing about yesterday felt way different than what a Cup car, Next Gen car, feels like. That was good for me.
”I think the characteristics of the Indycar versus the Cup car, at least at Phoenix, felt very similar. You're just going a lot faster in an Indycar.
“The moments happen a lot quicker. The edge of good versus not good feels a lot sharper.”
Larson said he felt “like I got close to the limit”, but felt there was more speed left on the table.
“I felt like when the car was gripped up, I was close to optimising it I would like to think,” he said.
“It's so hard to say when it's just me out there. I wish there could have been one other guy there that I could judge myself off of, look at data and compare.”
With no one else participating in the test, Larson could only compare data from 2018, the last time the IndyCar Series raced at the one mile, low-banked tri-oval. As such, he feels he was “out there guessing and going off of feel, which is kind of cool because it's like old-school style testing”.
Comparing the test to his only previous outing behind the wheel of an Indycar, at the Indianapolis Motor Speedway last October to complete all three phases of the Rookie Orientation Programme, he said the experience was “probably more uncomfortable just because it's a smaller track”.
“Things are happening quicker, you're having to lift off the throttle a little bit,” he explained.
“At Indy, once we got through the different stages and stuff, we were wide open pretty easy by yourself. It was a cool day and all that.
“Yesterday was fun to kind of have to work on the timing of the corner and work through some balance things because the balance was definitely not perfect, which was good to feel.”
