cleveref and subcaption: how to handle subfigure reference?

Question

Given

\usepackage{caption}
\usepackage{subcaption}
\usepackage{cleveref}
\crefname{subfigure}{figure}{figures}
\Crefname{subfigure}{Figure}{Figures}

\begin{figure}[h]
\centering
\begin{subfigure}{.5\textwidth}
\label{abc}
\caption{..}
\centering
\begin{tikzpicture}[scale=1]
\node at (0,1) {$d_1=1$};
\end{tikzpicture}
\end{subfigure}%
\begin{subfigure}{.5\textwidth}
\subcaption{...}
\label{...}
\centering
\begin{tikzpicture}[scale=1]
\node at (0,1) {$d_1=1$};
\end{tikzpicture}
\end{subfigure}
\caption{...}
\end{figure}

why does the command \cref{abc} not produce something like figure 2.a, but instead gives the name of the section ?