The difference in qualification times between Senna and Nakajima is jaw dropping. 8 (Eight) Seconds a lap in some cases.
https://www.gptoday.net/en/news/f1/246843/ayrton-senna-special-teammates-4-satoru-nakajima
Yeah, that was pretty extreme. But on the flipside, he scored points in all 5 seasons he competed, in an era where only the top 6 got points and pre-qualifying was a thing. He was clearly outclassed up against Senna - mostly because he never had even a fraction of Senna's raw talent, but also partly as it was his rookie season). My memory (rather vague nowadays looking back that far!) is that he was quite a bit better on race day than in qually, and definitely not the worst driver on the grid in the seasons he competed.