diff --git a/flow/scripts/util.tcl b/flow/scripts/util.tcl
index ab445ebd9b..e2ea5ae6ee 100644
--- a/flow/scripts/util.tcl
+++ b/flow/scripts/util.tcl
@@ -74,7 +74,10 @@ proc recover_power_helper { } {
 }
 
 proc extract_stage { input_file } {
-  if { ![regexp {/([0-9])_(([0-9])_)?} $input_file match num1 _ num2] } {
+  # Match the stage prefix on the basename, not the full path: an ancestor
+  # dir like ".../4_something/3_place.odb" would otherwise match "4_" -> stage 4.
+  set stage_file [file tail $input_file]
+  if { ![regexp {^([0-9])_(?:([0-9])_)?} $stage_file match num1 num2] } {
     puts "Error: Could not determine design stage from $input_file"
     exit 1
   }