diff --git a/src/Client/WorkflowClient.php b/src/Client/WorkflowClient.php
index cd6c7c11..885f7d2a 100644
--- a/src/Client/WorkflowClient.php
+++ b/src/Client/WorkflowClient.php
@@ -262,6 +262,7 @@ public function updateWithStart(
             $startArgs,
         );
 
+        // todo: set execution if UpdateWorkflow was failed but WF was started
         $workflowStub->setExecution($handle->getExecution());
 
         return $handle;
diff --git a/src/Internal/Client/ResponseToResultMapper.php b/src/Internal/Client/ResponseToResultMapper.php
new file mode 100644
index 00000000..db8f3033
--- /dev/null
+++ b/src/Internal/Client/ResponseToResultMapper.php
@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Temporal\Internal\Client;
+
+use Temporal\Api\Workflowservice\V1\UpdateWorkflowExecutionResponse;
+use Temporal\DataConverter\DataConverterInterface;
+use Temporal\DataConverter\EncodedValues;
+use Temporal\Exception\Client\WorkflowUpdateException;
+use Temporal\Exception\Failure\FailureConverter;
+use Temporal\Interceptor\WorkflowClient\StartUpdateOutput;
+use Temporal\Interceptor\WorkflowClient\UpdateRef;
+use Temporal\Workflow\WorkflowExecution;
+
+/**
+ * @internal
+ */
+final class ResponseToResultMapper
+{
+    public function __construct(
+        private readonly DataConverterInterface $converter,
+    ) {}
+
+    public function mapUpdateWorkflowResponse(
+        UpdateWorkflowExecutionResponse $result,
+        string $updateName,
+        string $workflowType,
+        WorkflowExecution $workflowExecution,
+    ): StartUpdateOutput {
+        $outcome = $result->getOutcome();
+        $updateRef = $result->getUpdateRef();
+        \assert($updateRef !== null);
+        $updateRefDto = new UpdateRef(
+            new WorkflowExecution(
+                (string)$updateRef->getWorkflowExecution()?->getWorkflowId(),
+                $updateRef->getWorkflowExecution()?->getRunId(),
+            ),
+            $updateRef->getUpdateId(),
+        );
+
+        if ($outcome === null) {
+            // Not completed
+            return new StartUpdateOutput($updateRefDto, false, null);
+        }
+
+        $failure = $outcome->getFailure();
+        $success = $outcome->getSuccess();
+
+
+        if ($success !== null) {
+            return new StartUpdateOutput(
+                $updateRefDto,
+                true,
+                EncodedValues::fromPayloads($success, $this->converter),
+            );
+        }
+
+        if ($failure !== null) {
+            $execution = $updateRef->getWorkflowExecution();
+            throw new WorkflowUpdateException(
+                null,
+                $execution === null
+                    ? $workflowExecution
+                    : new WorkflowExecution($execution->getWorkflowId(), $execution->getRunId()),
+                workflowType: $workflowType,
+                updateId: $updateRef->getUpdateId(),
+                updateName: $updateName,
+                previous: FailureConverter::mapFailureToException($failure, $this->converter),
+            );
+        }
+
+        throw new \RuntimeException(
+            \sprintf(
+                'Received unexpected outcome from update request: %s',
+                $outcome->getValue(),
+            ),
+        );
+    }
+}
diff --git a/src/Internal/Client/WorkflowStarter.php b/src/Internal/Client/WorkflowStarter.php
index dc574375..f108feaf 100644
--- a/src/Internal/Client/WorkflowStarter.php
+++ b/src/Internal/Client/WorkflowStarter.php
@@ -19,6 +19,7 @@
 use Temporal\Api\Update\V1\Request as UpdateRequestMessage;
 use Temporal\Api\Workflowservice\V1\ExecuteMultiOperationRequest;
 use Temporal\Api\Workflowservice\V1\ExecuteMultiOperationRequest\Operation;
+use Temporal\Api\Workflowservice\V1\ExecuteMultiOperationResponse\Response;
 use Temporal\Api\Workflowservice\V1\SignalWithStartWorkflowExecutionRequest;
 use Temporal\Api\Workflowservice\V1\StartWorkflowExecutionRequest;
 use Temporal\Api\Workflowservice\V1\UpdateWorkflowExecutionRequest;
@@ -187,7 +188,7 @@ function (UpdateWithStartInput $input): UpdateHandle {
                 ];
 
                 try {
-                    $this->serviceClient->ExecuteMultiOperation(
+                    $response = $this->serviceClient->ExecuteMultiOperation(
                         (new ExecuteMultiOperationRequest())
                             ->setNamespace($this->clientOptions->namespace)
                             ->setOperations($ops),
@@ -222,16 +223,37 @@ function (UpdateWithStartInput $input): UpdateHandle {
                     );
                 }
 
+                // Extract result
+                /** @var \ArrayAccess<int, Response> $responses */
+                $responses = $response->getResponses();
+
+                // Start Workflow: get execution
+                $startResponse = $responses[0]->getStartWorkflow();
+                \assert($startResponse !== null);
+                $execution = new WorkflowExecution($input->workflowStartInput->workflowId, $startResponse->getRunId());
+
+                // Update Workflow: get handler
+                $updateResponse = $responses[1]->getUpdateWorkflow();
+                \assert($updateResponse !== null);
+
+                $updateResult = (new \Temporal\Internal\Client\ResponseToResultMapper($this->converter))
+                    ->mapUpdateWorkflowResponse(
+                        $updateResponse,
+                        updateName: $input->updateInput->updateName,
+                        workflowType: $input->workflowStartInput->workflowType,
+                        workflowExecution: $execution,
+                    );
+
                 return new UpdateHandle(
                     client: $this->serviceClient,
                     clientOptions: $this->clientOptions,
                     converter: $this->converter,
-                    execution: $input->updateInput->workflowExecution,
+                    execution: $updateResult->getReference()->workflowExecution,
                     workflowType: $input->updateInput->workflowType,
                     updateName: $input->updateInput->updateName,
                     resultType: $input->updateInput->resultType,
-                    updateId: $input->updateInput->updateId,
-                    result: null,
+                    updateId: $updateResult->getReference()->updateId,
+                    result: $updateResult->getResult(),
                 );
             },
             /** @see WorkflowClientCallsInterceptor::updateWithStart() */
diff --git a/src/Internal/Client/WorkflowStub.php b/src/Internal/Client/WorkflowStub.php
index 9d85c55e..31ad5c1d 100644
--- a/src/Internal/Client/WorkflowStub.php
+++ b/src/Internal/Client/WorkflowStub.php
@@ -338,52 +338,13 @@ static function (
                     throw new WorkflowServiceException(null, $input->workflowExecution, $input->workflowType, $e);
                 }
 
-                $outcome = $result->getOutcome();
-                $updateRef = $result->getUpdateRef();
-                \assert($updateRef !== null);
-                $updateRefDto = new UpdateRef(
-                    new WorkflowExecution(
-                        (string) $updateRef->getWorkflowExecution()?->getWorkflowId(),
-                        $updateRef->getWorkflowExecution()?->getRunId(),
-                    ),
-                    $updateRef->getUpdateId(),
-                );
-
-                if ($outcome === null) {
-                    // Not completed
-                    return new StartUpdateOutput($updateRefDto, false, null);
-                }
-
-                $failure = $outcome->getFailure();
-                $success = $outcome->getSuccess();
-
-
-                if ($success !== null) {
-                    return new StartUpdateOutput(
-                        $updateRefDto,
-                        true,
-                        EncodedValues::fromPayloads($success, $converter),
+                return (new \Temporal\Internal\Client\ResponseToResultMapper($converter))
+                    ->mapUpdateWorkflowResponse(
+                        $result,
+                        $input->updateName,
+                        $input->workflowType,
+                        $input->workflowExecution,
                     );
-                }
-
-                if ($failure !== null) {
-                    $execution = $updateRef->getWorkflowExecution();
-                    throw new WorkflowUpdateException(
-                        null,
-                        $execution === null
-                            ? $input->workflowExecution
-                            : new WorkflowExecution($execution->getWorkflowId(), $execution->getRunId()),
-                        workflowType: $input->workflowType,
-                        updateId: $updateRef->getUpdateId(),
-                        updateName: $input->updateName,
-                        previous: FailureConverter::mapFailureToException($failure, $converter),
-                    );
-                }
-
-                throw new \RuntimeException(\sprintf(
-                    'Received unexpected outcome from update request: %s',
-                    $outcome->getValue(),
-                ));
             },
             /** @see WorkflowClientCallsInterceptor::update() */
             'update',
diff --git a/tests/Acceptance/Extra/Update/UpdateWithStartTest.php b/tests/Acceptance/Extra/Update/UpdateWithStartTest.php
index 4e78a93e..cf95d858 100644
--- a/tests/Acceptance/Extra/Update/UpdateWithStartTest.php
+++ b/tests/Acceptance/Extra/Update/UpdateWithStartTest.php
@@ -52,9 +52,10 @@ public function failWithBadUpdateName(
         );
 
         try {
-            $this->expectException(WorkflowUpdateException::class);
             $client->updateWithStart($stub, 'await1234', ['key']);
             $this->fail('Update must fail');
+        } catch (WorkflowUpdateException $e) {
+            $this->assertStringContainsString('await1234', $e->getPrevious()->getMessage());
         } finally {
             try {
                 $stub->getResult(timeout: 1);