You presume Link won because the ToP left Ganondorf. No.

The ToP left Ganondorf as a consequence of Link killing him, not as a cause. Before attaining the power of the ToP, the Sages struck a blade of light into his chest, which left a mortal wound. When Link struck that wound with the blade of evil's bane, Ganondorf's power of Darkness failed him, and thus did the ToP.

__________________

What if Majora's Mask was never made? / The last interesting timeline topic on ZU /
Disproving the Divine Prank myth