diff --git a/lib/tempest b/lib/tempest
index 5c9a67c596..507a3ed009 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -542,7 +542,10 @@ function configure_tempest {
     if [[ "$OFFLINE" != "True" ]]; then
         tox -revenv-tempest --notest
     fi
-    tox -evenv-tempest -- pip install -c $REQUIREMENTS_DIR/upper-constraints.txt -r requirements.txt
+
+    # The requirements might be on a different branch, while tempest needs master requirements.
+    git -C $REQUIREMENTS_DIR show master:upper-constraints.txt > u-c-m.txt
+    tox -evenv-tempest -- pip install -c u-c-m.txt -r requirements.txt
 
     # Auth:
     iniset $TEMPEST_CONFIG auth tempest_roles "Member"