Low-Rate Denial of Service (LDoS) attacks raise an increasingly frequent and significant threat to performancecritical and sensitive networks. Due to their slowly evolving nature, it is challenging –but crucial– to detect such attacks during their early phases in order to mitigate their impact on network performance, e.g. Quality of Service (QoS), in longterm operation. To this end, this paper investigates the prediction of QoS via a modified version of the Recurrent Trend Predictive Neural Network (rTPNN) and the use of the prediction towards detracting LDoS attacks. The presented rTPNN-based QoS predictor is evaluated and compared against benchmark models for five scenarios using an open-access dataset. The results have shown that the modified rTPNN model can predict QoS with under 2% SMAPE, and the QoS prediction is a promising approach for developing LDoS attack detectors in future works.