Tsunoda impressed in his maiden session with Red Bull, logging the sixth-fastest time in opening practice for the Japanese Grand Prix.
That left him only a tenth away from his vastly more accomplished teammate, Max Verstappen, despite his dearth of experience with the car.
Tsunoda was only confirmed in the Red Bull late last week, with the opening hour in Suzuka his first time at the wheel of the RB21.
However, there were strong indications off the back of the Chinese Grand Prix that changes were likely.
“I can’t say specific details, to be honest,” Tsunoda said of how the situation unfolded.
“The first call I got was from Christian Horner after China, saying maybe be prepared, things might change a little bit. That was around Monday or Tuesday.
“I was in the UK for preparation for Suzuka – that was already planned.
“I did a simulator session with Red Bull Racing, at that point it was just in case.
“Within two or three days in the UK, he confirmed it in person.”
Tsunoda’s promotion came after he was looked over for the seat at the end of last year.
Head to head with Lawson at that point, the New Zealander was thought to be a stronger prospect.
It proved too big an ask, and after two races he was brutally demoted back to Racing Bulls.
“It was brutal enough last year at the end of the season when they chose Liam over me,” Tsunoda said of his reaction to Lawson’s fate.
“It is what it is. I’m sure Liam also understands how quickly things can change within our structure.
“That’s one of the reasons we succeed, but also one of the reasons why we tend to get a little more attention with those situations.
“I have confidence,” he added.
“I’m not saying I have the confidence that I can perform straight away like Max, but I have confidence that I can do something different – hopefully – compared to other drivers that will be in the car.
“Racing Bulls already have such a good car, and I understand how they extract performance in every race so far but because I wanted to have a new challenge, and I have good confidence to challenge myself, so that’s why I’m wearing this and hitting the track with a different livery.”
It sees Tsunoda arrive at his home grand prix with the potential of becoming only the third Japanese driver to stand on an F1 podium.
“Can’t be crazier than this, I guess, this situation,” he noted.
“First race in Red Bull Racing and on top of it, a home grand prix.
“I think it’s the best situation ever. I’m just excited.”
Without time to perform any real world testing, Tsunoda’s simulator sessions offered a useful insight into the challenge that awaits him, though wasn’t able to paint a complete picture of the car’s nuances.
“I didn’t feel yet the exact trickiness that the drivers are saying,” he said of the sim sessions.
“I have a bit of an idea from the simulator but it’s always a bit different from simulator to real car, so I’ll see after FP1 if I either have to change set-up or….
“I don’t think I’ll have to change my driving style because, in the end, so far it works well I guess with VCARB, otherwise I wouldn’t be here wearing this logo.
“I will just do whatever I was doing previously and I’ll just go step by step to build the pace and everything.
“Let’s see. Maybe I don’t have to do that. Maybe the car is straightaway good.”
