diff --git a/test_runner/fixtures/neon_fixtures.py b/test_runner/fixtures/neon_fixtures.py
index 4b23650960..7dfdd9274d 100644
--- a/test_runner/fixtures/neon_fixtures.py
+++ b/test_runner/fixtures/neon_fixtures.py
@@ -1870,11 +1870,12 @@ class NeonPageserver(PgProtocol):
         tenant_id: TenantId,
         conf: Optional[Dict[str, Any]] = None,
         auth_token: Optional[str] = None,
+        generation: Optional[int] = None,
     ) -> TenantId:
+        if generation is None:
+            generation = self.maybe_get_generation(tenant_id)
         client = self.http_client(auth_token=auth_token)
-        return client.tenant_create(
-            tenant_id, conf, generation=self.maybe_get_generation(tenant_id)
-        )
+        return client.tenant_create(tenant_id, conf, generation=generation)
 
     def tenant_load(self, tenant_id: TenantId):
         client = self.http_client()
diff --git a/test_runner/performance/test_bulk_insert.py b/test_runner/performance/test_bulk_insert.py
index a146e011cc..a2a1fa11e5 100644
--- a/test_runner/performance/test_bulk_insert.py
+++ b/test_runner/performance/test_bulk_insert.py
@@ -55,9 +55,20 @@ def measure_recovery_time(env: NeonCompare):
 
     # Delete the Tenant in the pageserver: this will drop local and remote layers, such that
     # when we "create" the Tenant again, we will replay the WAL from the beginning.
+    #
+    # This is a "weird" thing to do, and can confuse the attachment service as we're re-using
+    # the same tenant ID for a tenant that is logically different from the pageserver's point
+    # of view, but the same as far as the safekeeper/WAL is concerned.  To work around that,
+    # we will explicitly create the tenant in the same generation that it was previously
+    # attached in.
+    assert env.env.attachment_service is not None
+    attach_status = env.env.attachment_service.inspect(tenant_id=env.tenant)
+    assert attach_status is not None
+    (attach_gen, _) = attach_status
+
     client.tenant_delete(env.tenant)
     wait_tenant_status_404(client, env.tenant, iterations=60, interval=0.5)
-    env.env.pageserver.tenant_create(tenant_id=env.tenant)
+    env.env.pageserver.tenant_create(tenant_id=env.tenant, generation=attach_gen)
 
     # Measure recovery time
     with env.record_duration("wal_recovery"):