diff --git a/tests/benchmarks/testlib/tostring/tst_tostring.cpp b/tests/benchmarks/testlib/tostring/tst_tostring.cpp
index 1731929f983..a1c4aba9165 100644
--- a/tests/benchmarks/testlib/tostring/tst_tostring.cpp
+++ b/tests/benchmarks/testlib/tostring/tst_tostring.cpp
@@ -95,7 +95,8 @@ void tst_toString::numeric()
     QFETCH(T, datum);
 
     QBENCHMARK {
-        QTest::toString<T>(datum);
+        auto tst = QTest::toString<T>(datum);
+        delete [] tst;
     }
 }