When a relatively thick (-10μm or more) polymer film doped with laser dyes was coated on a thick Ag island film (TAIF) cosisting of large psedudotabular nanoparticles and pumped by a nanosecond laser pulse, the extremely enhanced radiative rate (much faster emission) achieved very near the metal surface triggered an avalanch of stimulated emission from the dye-doped polymer film, producing a single sharp laser-like emision with bandwidth as small as 2.5nm. This does not need any special feeback mechanism, not to mention an external cavity. The fact that this novel lasing action was induced by the surface-enhanced fluoresence was verified by the fact that the separation of TAIF and the dye-doped polymer film by a molecularly thin spacer only -10 Å thick was sufficient to suprress the lasing action.