O'Ward impressed on his latest appearance in McLaren's F1 machinery by finishing second in Abu Dhabi's post-season test, completing 103 laps in the 2023 MCL60 to put himself just 0.269s behind Alpine's leading Esteban Ocon.
His outing came days after being announced as one of McLaren's 2024 reserve drivers, having already completed private tests in the 2021 MCL35 as well as several FP1 sessions.
O'Ward will focus on his 2024 IndyCar campaign before joining the F1 team in his reserve role from September's Singapore Grand Prix onwards.
His Abu Dhabi test is the latest step towards a dream F1 seat, although the 24-year-old Mexican says his priority remains to win an Indy 500 for McLaren after narrowly losing out to Marcus Ericsson in 2022.
When asked if he felt closer to an F1 seat than ever, O'Ward said: "Absolutely, every time you do more FP1s or more testing, that's just more time in the car.
"And that means someone is ultimately believing in you and giving you that opportunity to be ready if those doors do open.
"I'm fully focused on what I have to do in IndyCar because I want to give the 500 win to McLaren, I want to be the one that gives it to them because I've been with them for four years, starting my fifth next year.
"And then it would be quite the Cinderella story to tackle the challenge in Formula 1 and be a contender, not just to come here and have fun."
When asked to expand on his 103-lap test, O'Ward said he was pleased with how he continued finding gains until his final soft-tyre runs.
"From the start of the day to the end of the day, and even from my second to last soft run to my last soft run, the learning that I was doing corner by corner was huge," he explained.
"I think I'm fairly close [to the limit]. I think there's still [a bit] to go, but I got to a really nice place today where I felt like I was on top of the car.
"I did over 100 laps today and my neck was a champ, I'm so proud.
"You have no idea how much work I've done on my neck the past two years. I have destroyed it day and day after day to withstand what these cars are capable of."
O'Ward feels his F1 duties will make him a better driver regardless of his future career path, as he gears up to improve on his fourth place in 2023's IndyCar standings.
"If you want to be a champion, you need to put yourself into these uncomfortable positions in order to grow," he explained.
"It takes a lot of work, a lot of fine detail and it can get really frustrating sometimes, but I've had to work really hard to get where I've gotten to, so for me it's a nice challenge to accept.
"If it ends up happening, fantastic. I know I'm good enough to be here. But if it doesn't, it's just going to make me better everywhere else."
