diff --git a/t/perf/p5332-multi-pack-reuse.sh b/t/perf/p5332-multi-pack-reuse.sh
index 5c6c575d62..9526ba7c31 100755
--- a/t/perf/p5332-multi-pack-reuse.sh
+++ b/t/perf/p5332-multi-pack-reuse.sh
@@ -58,7 +58,7 @@ do
 	'
 
 	test_expect_success "setup bitmaps for $nr_packs-pack scenario" '
-		find $packdir -type f -name "*.idx" | sed -e "s/.*\/\(.*\)$/+\1/g" |
+		find $packdir -type f -name "*.idx" | sed -e "s/.*\///" |
 		git multi-pack-index write --stdin-packs --bitmap \
 			--preferred-pack="$(find_pack $(git rev-parse HEAD))"
 	'