Forres came into the match on the back of thumping wins over Fraserburgh and Formartine, but were brought back to earth by an on-song Locos outfit, who ran out 3-1 winners after grabbing two late goals.
Buchan said: "This was a fantastic game to win. I cannot say enough good things about the guys. The second-half performance in particular was stunning. It's a long season but as long as we keep pushing I'm sure we'll be up there with the title challengers."
Locos went 1-0 up through a Craig Ross strike after 23 minutes, but Kevin Duguid looked to have rescued Forres a point with only 10 minutes left.
Locos were not to be denied, however, with Neil Gauld and Ross again netting in the closing minutes.
Elsewhere, Turriff United went joint top of the table with reigining champions Buckie after a 5-2 win at Wick, in a game which featured a double from Grant Noble. Buckie, though, lead on goal difference with three games in hand.