diff --git a/Makefile b/Makefile
index d06bac5..399f0f8 100644
--- a/Makefile
+++ b/Makefile
@@ -39,6 +39,14 @@ SOURCES_plot_plates := $(TARGETS_signif_wells)
 TARGETS_plot_plates := $(addsuffix results/plots/,)
 TARGETS_plots := $(TARGETS_plot_overlap) $(TARGETS_plot_plates)
 
+# Functions
+#
+# Hack of single rule invocation for multiple targets by substituting
+# file extension "." with "%" per http://stackoverflow.com/a/3077254
+define singleton
+$(foreach path,$1,$(shell echo -n $(path) | sed 's#\(.*\)\.#\1%##'))
+endef
+
 .PHONY : all
 all : z-projection cellprofiler plots ## (Default) Run full pipeline from image processing to plots.
 
@@ -62,7 +70,7 @@ $(TARGETS_img_zproj) : $(SOURCES_img_zproj)
 
 .PHONY : cellprofiler
 cellprofiler : $(TARGETS_cellprofiler) ## Collect statistics about all images.
-$(TARGETS_cellprofiler) : $(SOURCES_cellprofiler)
+$(call singleton,$(TARGETS_cellprofiler)) : $(SOURCES_cellprofiler)
 	$(CELLPROFILER) $(CELLPROFILER_OPTS) --run-headless
 
 .PHONY : gui-cellprofiler