On reflection it is impossible to look past WG Grace in 1871.
In all first-class matches in 1871, a total of 17 centuries were scored and WG Grace scored 10 of them. Please consider for a moment about what a ridiculous statistic that is.
His run-scoring aggregate for the season was 2,739; the next best was 1,068. Grace also averaged virtually double what the next best batsman averaged.
Oh and Grace also took 79 wickets at 17, which is to say about 61 points lower than his batting average that season.
That is dominance-at-peak of a kind which can never have been seen - in any sport - before or since.
We can't help regarding Grace as a comically fat old man with an enormous stomach and a silly beard, but that's really just an accident of the history of photography: just about all the pictures we see of him are from the arse end of a ridiculously long career, 3 decades or more after his 1871 annus mirabilis. But in his un-photographed youth he was quite the athlete (famously winning the national 440 yards hurdles title in 1866, which is virtually impossible to imagine given his portly appearance in the photographs taken in his autumn years). I can't help thinking that if there were more photos of the great man in his youth, we'd tend to take him more seriously as what he quite possibly was, namely the greatest player in the history of the game.
But whether or not he eclipses Bradman or (hah!) Tendulkar as the greatest player ever when judged over an entire career, as for "dominance at peak", well, you can forget about the competition. The Grace of 1871 remains head and shoulders above them all.