Coopetition has become a heated issue in the last decade. In this study, a scrutinized review of previous research on coopetition is presented to clarify the research stream on coopetition, from which the implications are derived and a framework to analyse the phenomenon is proposed. Given the complex nature of coopetition, an in-depth case study was undertaken to investigate the competition–cooperation relationship and coopetition performance over a 15-year period in a Taiwanese supermarket network, which was formed by a focal company and its competitors. Performance was analysed before and after launching the coopetition strategy, in which 31 indicators were examined. The findings imply that competition (Yang) and cooperation (Yin) are reciprocally rooted in and mutually promoted by each other. The findings also confirmed that cooperation with competitors did lead to better performance, at least over a period, in two ways. The first was that the adoption of coopetition permitted the attainment of performance levels beyond what would otherwise have been possible; the second was that the adoption of coopetition changed the timeframe, permitting earlier achievement of higher performance levels. This study contributes to and extends knowledge of the dynamics and consequences of cooperation with competitors and demonstrates that coopetition has a significant temporary advantage.