Another way uses a bit of VBA. Not to neat but it does the trick. I expect
someone will come up with a more concise solution;

For a = 2 To 20 'or whatever the range is
If Cells(a, 1) < Cells(a, 1).Offset(-1, 0) Or Cells(a, 1) Cells(a,
1).Offset(-1, 0) Then
Cells(a, 1).Interior.ColorIndex = 6
End If
Next