The Battle of the Golden Spurs would be a better example, with several French nobles (such as the Marshal of France and the Constable of France!) ultimately losing their lives to pikemen. All the more surprising because this was pretty much the first battle in Medieval history where the side with the most knights lost (quite badly).

Admittedly, the Flemish side wasn't exactly peasantry but largely townspeople in guilds, although in terms of the classic three-tier model (nobility, clergy, peasantry), they would have fallen into the last class.