We explore the role of experience in mixed-strategy games by comparing the behavior of novice poker players to the behavior of expert players who have extensive experience playing poker online. Our experimental game is a simplified representation of heads-up play in Texas Hold-em, where one player (the "small blind") has an incentive to steal the ante/blind of the other player (the "big blind"). We find significant differences in their play. The initial frequencies with which experts bet and call are closer to the equilibrium frequencies than are those of novice players. And, while the betting and calling frequencies of both novices and experts exhibit too much heterogeneity to be consistent with minimax play, the frequencies of experts exhibit less heterogeneity. There is no evidence of learning by the experts. In contrast, the betting and calling frequencies of novices move substantially closer to the equilibrium frequencies over the course of the experiment.