diff --git a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
index a4ad6f606..a4a544e60 100644
--- a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
+++ b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java
@@ -415,7 +415,7 @@ public class FunctionConfiguration {
 					? ((BindableFunctionProxyFactory) bindableProxyFactory).getOutputName(0)
 							: (FunctionTypeUtils.isConsumer(functionType) ? null : "output");
 
-			if (FunctionTypeUtils.isReactive(FunctionTypeUtils.getInputType(functionType, 0))) {
+			if (FunctionTypeUtils.isReactive(FunctionTypeUtils.getInputType(functionType, 0)) && StringUtils.hasText(outputChannelName)) {
 				MessageChannel outputChannel = context.getBean(outputChannelName, MessageChannel.class);
 				SubscribableChannel subscribeChannel = (SubscribableChannel) inputChannel;
 				Publisher<?> publisher = this.enhancePublisher(MessageChannelReactiveUtils.toPublisher(subscribeChannel),
diff --git a/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java b/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
index 19179e44d..c9a364da1 100644
--- a/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
+++ b/spring-cloud-stream/src/test/java/org/springframework/cloud/stream/function/ImplicitFunctionBindingTests.java
@@ -167,6 +167,25 @@ public class ImplicitFunctionBindingTests {
 		}
 	}
 
+	@Test
+	public void testReactiveConsumerWithoutDefinitionProperty() {
+		System.clearProperty("spring.cloud.stream.function.definition");
+		try (ConfigurableApplicationContext context = new SpringApplicationBuilder(
+				TestChannelBinderConfiguration.getCompleteConfiguration(
+						SingleReactiveConsumerConfiguration.class))
+								.web(WebApplicationType.NONE)
+								.run("--spring.jmx.enabled=false")) {
+
+			InputDestination inputDestination = context.getBean(InputDestination.class);
+			Message<byte[]> inputMessage = MessageBuilder
+					.withPayload("Hello".getBytes()).build();
+			inputDestination.send(inputMessage);
+
+			assertThat(System.getProperty("consumer")).isEqualTo("Hello");
+			System.clearProperty("consumer");
+		}
+	}
+
 	@Test
 	public void testConsumer() {
 		try (ConfigurableApplicationContext context = new SpringApplicationBuilder(
@@ -396,6 +415,18 @@ public class ImplicitFunctionBindingTests {
 		}
 	}
 
+	@EnableAutoConfiguration
+	public static class SingleReactiveConsumerConfiguration {
+
+		@Bean
+		public Consumer<Flux<String>> consumer() {
+			return flux -> flux.subscribe(value -> {
+				System.out.println(value);
+				System.setProperty("consumer", value);
+			});
+		}
+	}
+
 	@EnableAutoConfiguration
 	public static class ReactiveFunctionConfiguration {