diff --git a/src/gallium/auxiliary/draw/draw_pipe_unfilled.c b/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
index 8cba07c34bc..4f0326bf399 100644
--- a/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
+++ b/src/gallium/auxiliary/draw/draw_pipe_unfilled.c
@@ -81,6 +81,7 @@ inject_front_face_info(struct draw_stage *stage,
       v->data[slot][1] = is_front_face;
       v->data[slot][2] = is_front_face;
       v->data[slot][3] = is_front_face;
+      v->vertex_id = UNDEFINED_VERTEX_ID;
    }
 }