SUZUKA, Japan (AP) — Four-time world champion Max Verstappen has not ruled out retiring at the end of the Formula 1 season, saying he is trying “very hard” to enjoy racing under the new changes . The Red Bull driver again openly expressed his dissatisfaction on Sunday after an eighth-place finish at the Japanese Grand Prix , which was won by 19-year-old Kimi Antonelli of Mercedes. “Privately I’m very happy,” Verstappen told the BBC after the race. “You also wait for 24 races. This time it’s 22 .