Not surprisingly, Rafael Nadal couldn’t take a step around the grounds of the Davis Cup Final 8 in recent days without hearing requests for a handshake or a selfie. The significance of Nadal’s retirement is lost on no one inside or outside the sport he is walking away from at age 38 after a litany of injuries, and for all of the well-documented success he enjoyed, his greatest legacy might be the way he inspired other players. The 22-time Grand Slam champion and all-time great of the game lost the last match of his career as Spain was eliminated by the Netherlands in the quarterfinals as Tuesday turned to Wednesday.