diff --git a/pallets/parachain-system/src/lib.rs b/pallets/parachain-system/src/lib.rs
index e10f628abf..a9d1446f46 100644
--- a/pallets/parachain-system/src/lib.rs
+++ b/pallets/parachain-system/src/lib.rs
@@ -1049,7 +1049,14 @@ impl<T: Config> BlockNumberProvider for RelaychainBlockNumberProvider<T> {
 	}
 	#[cfg(feature = "runtime-benchmarks")]
 	fn set_block_number(block: Self::BlockNumber) {
-		let mut validation_data = Pallet::<T>::validation_data().unwrap_or_default();
+		let mut validation_data = Pallet::<T>::validation_data().unwrap_or_else(||
+			// PersistedValidationData does not impl default in non-std
+			PersistedValidationData {
+				parent_head: vec![].into(),
+				relay_parent_number: Default::default(),
+				max_pov_size: Default::default(),
+				relay_parent_storage_root: Default::default(),
+			});
 		validation_data.relay_parent_number = block;
 		ValidationData::<T>::put(validation_data)
 	}