Classic methods for sinusoidal analysis rely on partial tracking, a technique where successive sets of spectral peaks of an audio signal must be properly associated in time. The resulting tracks describe, in terms of amplitude and frequency, the continuous evolution of the so-called partials which, combined, model the complex sounds emitted by a given instrument. A well-known challenge in this context is preserving amplitude and frequency coherence in the tracking mechanism, specially in cases where failure in peak detection may occur, or perhaps in the event of crossing partials. This paper presents a new decision-directed recursive least-squares (RLS) estimation method for frequency and amplitude tracking in sinusoidal analysis. Different performance measurements show that the proposed deterministic algorithm outperforms some procedures currently found in the literature.