diff --git a/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java b/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
index d7868ae4e..990b642dc 100644
--- a/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
+++ b/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
@@ -32,6 +32,7 @@ import reactor.core.publisher.Mono;
 import org.springframework.cloud.function.context.FunctionCatalog;
 import org.springframework.cloud.function.context.FunctionProperties;
 import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
+import org.springframework.cloud.function.context.config.RoutingFunction;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.ReactiveAdapterRegistry;
@@ -154,6 +155,9 @@ class FunctionRSocketMessageHandler extends RSocketMessageHandler {
 	@SuppressWarnings("unchecked")
 	private String discoverAndInjectDestinationHeader(Message<?> message) {
 		String destination = this.functionProperties.getDefinition();
+		if (!StringUtils.hasText(destination) && StringUtils.hasText(this.functionProperties.getRoutingExpression())) {
+			destination = RoutingFunction.FUNCTION_NAME;
+		}
 		Map<String, Object> headersMap = (Map<String, Object>) ReflectionUtils
 				.getField(this.headersField, message.getHeaders());
 
diff --git a/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationRoutingTests.java b/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationRoutingTests.java
index 88e45c13f..e37a9b900 100644
--- a/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationRoutingTests.java
+++ b/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationRoutingTests.java
@@ -58,7 +58,7 @@ public class RSocketAutoConfigurationRoutingTests {
 				applicationContext.getBean(RSocketRequester.Builder.class);
 
 			rsocketRequesterBuilder.tcp("localhost", port)
-				.route(RoutingFunction.FUNCTION_NAME)
+				.route("")
 				.metadata("{\"func_name\":\"echo\"}", MimeTypeUtils.APPLICATION_JSON)
 				.data("hello")
 				.retrieveMono(String.class)
@@ -68,14 +68,14 @@ public class RSocketAutoConfigurationRoutingTests {
 				.verify();
 
 			rsocketRequesterBuilder.tcp("localhost", port)
-			.route(RoutingFunction.FUNCTION_NAME)
-			.metadata("{\"func_name\":\"uppercase\"}", MimeTypeUtils.APPLICATION_JSON)
-			.data("hello")
-			.retrieveMono(String.class)
-			.as(StepVerifier::create)
-			.expectNext("HELLO")
-			.expectComplete()
-			.verify();
+				.route(RoutingFunction.FUNCTION_NAME)
+				.metadata("{\"func_name\":\"uppercase\"}", MimeTypeUtils.APPLICATION_JSON)
+				.data("hello")
+				.retrieveMono(String.class)
+				.as(StepVerifier::create)
+				.expectNext("HELLO")
+				.expectComplete()
+				.verify();
 		}
 	}
 
diff --git a/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationTests.java b/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationTests.java
index 8fa77132c..0a1531050 100644
--- a/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationTests.java
+++ b/spring-cloud-function-rsocket/src/test/java/org/springframework/cloud/function/rsocket/RSocketAutoConfigurationTests.java
@@ -122,6 +122,31 @@ public class RSocketAutoConfigurationTests {
 		}
 	}
 
+	@Test
+	public void testWithRouteAndDefinition() {
+		int port = SocketUtils.findAvailableTcpPort();
+		try (
+			ConfigurableApplicationContext applicationContext =
+				new SpringApplicationBuilder(SampleFunctionConfiguration.class)
+					.web(WebApplicationType.NONE)
+					.run("--logging.level.org.springframework.cloud.function=DEBUG",
+							"--spring.cloud.function.definition=echo",
+						"--spring.rsocket.server.port=" + port);
+		) {
+			RSocketRequester.Builder rsocketRequesterBuilder =
+				applicationContext.getBean(RSocketRequester.Builder.class);
+
+			rsocketRequesterBuilder.tcp("localhost", port)
+				.route("uppercase")
+				.data("hello")
+				.retrieveMono(String.class)
+				.as(StepVerifier::create)
+				.expectNext("HELLO")
+				.expectComplete()
+				.verify();
+		}
+	}
+
 	@Test
 	public void testImperativeFunctionAsRequestReplyWithComposition() {
 		int port = SocketUtils.findAvailableTcpPort();