diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 086f6a0bb4..6b155fc8bc 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -79,12 +79,13 @@ jobs:
             cd benchmarks/.asv/performance-shifts
             for commit_file in *
             do
-              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | tail -1 | cut -c 2-)
+              commit="${commit_file%.*}"
+              pr_number=$(git log "$commit"^! --oneline | grep -o "#[0-9]*" | tail -1 | cut -c 2-)
               assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo $GITHUB_REPOSITORY)
-              title="Performance Shift(s): \`$commit_file\`"
+              title="Performance Shift(s): \`$commit\`"
               body="
           Benchmark comparison has identified performance shifts at commit \
-          $commit_file (#$pr_number). Please review the report below and \
+          $commit (#$pr_number). Please review the report below and \
           take corrective/congratulatory action as appropriate \
           :slightly_smiling_face:
 
diff --git a/noxfile.py b/noxfile.py
index e4d91c6bab..c65319c35f 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -432,7 +432,7 @@ def asv_compare(*commits):
                     # Dir is used by .github/workflows/benchmarks.yml,
                     #  but not cached - intended to be discarded after run.
                     shifts_dir.mkdir(exist_ok=True, parents=True)
-                    shifts_path = shifts_dir / after
+                    shifts_path = (shifts_dir / after).with_suffix(".txt")
                     with shifts_path.open("w") as shifts_file:
                         shifts_file.write(shifts)