diff --git a/spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionHandlerMapping.java b/spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionHandlerMapping.java
index 3c9f03edf..1db849443 100644
--- a/spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionHandlerMapping.java
+++ b/spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionHandlerMapping.java
@@ -30,6 +30,7 @@ import org.springframework.cloud.function.context.FunctionInspector;
 import org.springframework.cloud.function.registry.FunctionCatalog;
 import org.springframework.cloud.function.web.flux.constants.WebRequestConstants;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.util.StringUtils;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
@@ -80,6 +81,9 @@ public class FunctionHandlerMapping extends RequestMappingHandlerMapping
 		}
 		String path = (String) request
 				.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
+		if (StringUtils.hasText(prefix) && !path.startsWith(prefix)) {
+			return null;
+		}
 		if (path.startsWith(prefix)) {
 			path = path.substring(prefix.length());
 		}
diff --git a/spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/PrefixTests.java b/spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/PrefixTests.java
index 8250b6707..606ca54fe 100644
--- a/spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/PrefixTests.java
+++ b/spring-cloud-function-web/src/test/java/org/springframework/cloud/function/web/PrefixTests.java
@@ -53,12 +53,19 @@ public class PrefixTests {
 
 	@Test
 	public void words() throws Exception {
-		ResponseEntity<String> result = rest
-				.exchange(RequestEntity.get(new URI("/functions/words")).build(), String.class);
+		ResponseEntity<String> result = rest.exchange(
+				RequestEntity.get(new URI("/functions/words")).build(), String.class);
 		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.OK);
 		assertThat(result.getBody()).isEqualTo("[\"foo\",\"bar\"]");
 	}
 
+	@Test
+	public void missing() throws Exception {
+		ResponseEntity<String> result = rest
+				.exchange(RequestEntity.get(new URI("/words")).build(), String.class);
+		assertThat(result.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
+	}
+
 	@EnableAutoConfiguration
 	@org.springframework.boot.test.context.TestConfiguration
 	protected static class TestConfiguration {