diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java b/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java
index 42ed13ae1f..6bf4f7bf38 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java
@@ -116,8 +116,8 @@ public abstract class AbstractJackson2Encoder extends Jackson2CodecSupport imple
 		JsonEncoding encoding = getJsonEncoding(mimeType);
 
 		if (inputStream instanceof Mono) {
-			return Flux.from(inputStream).map(value ->
-					encodeValue(value, mimeType, bufferFactory, elementType, hints, encoding));
+			return Mono.from(inputStream).map(value ->
+					encodeValue(value, mimeType, bufferFactory, elementType, hints, encoding)).flux();
 		}
 
 		for (MediaType streamingMediaType : this.streamingMediaTypes) {