A service-oriented architecture (SOA) for web applications is often implemented using web service (WS) standards and consists of different functions the executions of which are perceived as events. The order and time-appropriateness of occurrences of these events play a vital role for the proper working of a real-time SOA. This paper presents an event-based approach for modeling and testing of functional behavior of WS in SOA by event sequence graphs (ESG). Nodes of ESG represent events, e.g., "request" or "response", and arcs give the sequence of these events. For representing parameter values, e.g., for time-out of function calls, ESG are augmented by decision tables (DT). A case study carried out on a commercial web system with SOA validates the approach and analyzes its characteristic issues. The novelty of the approach stems from (i) its simplicity and lucidity in representing complex real-time web applications based on WS in SOA, and (ii) its modeling that considers a comfortable fault management.