  We study the spherically symmetric gravitational collapse of massless scalar
matter field in asymptotic flat spacetime in $f(R)$ gravity. In the Einstein
frame of $f(R)$ gravity, an additional scalar field arises due to the conformal
transformation. We find that besides the usual competition between
gravitational energy and kinetic energy in the process of gravitational
collapse, the new scalar field brought by the conformal transformation adds one
more competing force in the dynamical system. The dynamical competition can be
controlled by tuning the amplitudes of the initial perturbations of the new
scalar field and the matter field. To understand the physical reasons behind
these phenomena, we analyze the gravitational potential behavior and calculate
the Ricci scalar at center with the change of initial amplitudes of
perturbations. We find rich physics on the formation of black holes through
gravitational collapse in $f(R)$ gravity.
