We investigated informative acoustic feature extraction based on dimension reduction for collecting target sources on a noisy sports field. Although a Wiener filter is often used for sound source enhancement, it is difficult to accurately design the Wiener filter by simply using spatial cues because the noise on a sports field (e.g., cheering from spectators) arrives from the same direction as that of the targeted source. A statistical approach is used to estimate the Wiener filter by using pre-trained acoustic feature models. However, an informative acoustic feature, which provides a powerful clue for clear extraction of the target source, is unknown. For this study, we developed a method for optimizing a projection matrix for dimension reduction by maximizing the mutual information between acoustic features and the Wiener filter. Through experiments using two-directional microphones on a mock sports field, we confirmed that the proposed method outperformed previous methods in terms of both the noise reduction and quality of the recovered sound sources.