Stoffel Vandoorne says McLaren was almost completely focused on Fernando Alonso during his time with the once-great British team.
Belgian Vandoorne raced at McLaren with Honda and then Renault power in 2017 and 2018, but for 2019 has been dropped and is now a Mercedes simulator and Formula E driver.
He said of his F1 career: "It was not always easy. Actually, it was very difficult.
"My motor sport career went almost perfectly up until formula one," Vandoorne told the Dutch broadcaster Ziggo Sport.
"I won almost every championship I took part in.
"The timing at McLaren was probably not the best because the car has not been good for several years. Unfortunately it was not the best years in my career."
The 26-year-old confirmed the paddock perception that he suffered because of McLaren’s Alonso-centric focus.
"Yes," he said. "Unfortunately, I have never been able to tell 99 per cent of what happened."