why did Francois state that they would now be able to make good time, in Call of the Wild?

Buck and Spitz had their alpha-male fight to the death match. Buck won, Francois thinks they will make better time because Buck is the superior sled dog and there will be no more fighting between the two dogs,

"An' dat Buck fight like two hells," was Francois's answer. "And now we make good time. No more Spitz, no more trouble, sure."