Kriging in R, how to retain observation value in kriged data grid

How can I match kriged values to observation data?

library(sp)
data(meuse)
coordinates(meuse) = ~x+y
data(meuse.grid)
gridded(meuse.grid) = ~x+y

m <- vgm(.59, "Sph", 874, .04)

ordinary kriging:

x <- krige(zinc~1, meuse, meuse.grid, model = m)
[using ordinary kriging]

max(x$var1.pred)
[1] 1722.268

max(meuse$zinc)
[1] 1839

In this case, the predicted max value is slightly lower than the observed value. How can I retain observed data in a kriged data set representing the respective grid box?
Point to gird data conversion will have some differences, but I wish to have the gird with observation data have the same values.