PbZr1-xTixO3 perovskite materials, known as PZT, are highly applicable, mainly due to their extraordinary piezoelectric properties. Recently, a technology of PZT crystals growth has been elaborated and opened new investigation possibilities for these compounds. In this paper, we demonstrate a highly piezoelectric response in PbZr0.87Ti0.13O3 single crystal. Under the action of an electric field, the piezoelectric coefficient d33 turns out to be over 2500 pm V-1. The optical studies performed have proved a significant influence of the domain dynamics on such high-efficiency piezoelectric response. Monoclinic M and rhombohedral R phases have been observed in the lead zirconate-titanate crystals with a low Ti content. This coexistence of phases with different symmetries and dense domain walls are the primary sources of high piezoelectric response. We have observed that strong electric fields may act on randomly oriented polarization vectors so that the total piezoelectric activity disappears, and the unusual isotropization point near 250 °C appears.