Usually qualifying within fractions of one another, and thereby finding themselves together on the grid, race days usually witnessed the pair scrapping for the same piece of tarmac, often with alarming results.
Last year, though the Frenchman regularly out-qualified his Mexican teammate, it was Perez who scored the team's best result - the only non-Mercedes, Ferrari or Red Bull driver to make it to the podium - and finish higher in the overall standings.
Indeed it was Ocon's desperation to overhaul the 15-point advantage his teammate gained in Azerbaijan - the Frenchman making a reckless move on Kimi Raikkonen at the start that ended his race before it had begun - that led to further errors over the course of the year.
"It's like people just get used to me," he tells Motorsport.com. "When I was new here, everyone was talking about me and I was the next big thing, as Esteban is right now," he adds, though whether "next big thing" really applies to someone who was dropped by McLaren after just one season is debatable.
"Last year I was best of the rest," he continues, referring to 2017, "I've been beating all my teammates I've had. So results in the end talk more than what people say.
"Results are clear," he adds, moving forward to 2018. "He was the better one in qualifying, although the margin was extremely small. It is less than a tenth between us in qualifying. And I was the better one in the races. I got the most points and also the best results. But it was really close between us up to now."
Asked about Ocon's qualifying advantage, the Mexican says: "I didn't feel very confident this year with the car to be honest. I did struggle quite a lot throughout the year to balance the car, but I did manage to get the most out of it in the race.
"That's to take nothing away from him," he adds. "I didn't get on with it and he did better in qualifying. That's it. It is up to me and to my team to get the best out of the car
"I think in other years I've been more comfortable with the car on Saturday, and (last year) I probably focused quite a bit on Sundays too."