Previous research on idiosyncratic deals (i-deals) has treated them as concrete events, arguing that these i-deals shape employment relationships and impact on work performance over long periods of time. However, some types of i-deals may be negotiated and shaped over short periods of time. The aim of this research is to understand the social context within which these types of i-deals unfold and influence employee work performance. Focusing on task i-deals and adopting a weekly diary design approach, we explore the role of relationship quality with co-workers and managers that matter for the obtainment of task i-deals and how obtained task i-deals translate into work performance, over weeks. To explore our research questions, we collected weekly diary data (over 7 weeks; n = 67 employees; 67 co-workers and 23 managers) from employees, their co-workers and managers. The results from multi-level analyses demonstrate that weekly reports of co-worker support matter more to obtain task i-deals than employee's relationship quality with their manager. Furthermore, results underline that weekly structural job resources explain how and why obtained task i-deals lead to enhanced work performance over weeks. HR managers and practitioners can design task i-deals as short-term intervention tools to drive work performance.