This paper tests two hypotheses from the theory of elimination tournaments: (i) that uneven
tournaments, where the contestants are ex ante heterogeneous, entail lower effort exertion;
this is a prediction from agency theory that has not been tested empirically before; and (ii)
whether incentives set through prizes matter for effort exertion; this assumption underlies any
agency theory about elimination tournaments, and has been empirically tested in other
contexts. The evidence obtained with data from professional tennis tournaments supports
both the assumption that incentives matter, as well as the theoretical implications concerning
uneven tournaments among heterogeneous contestants.