diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
index f5fe5cd5ece..ec41e8cf6c3 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/JettyRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,6 @@
 
 package org.springframework.web.reactive.socket.server.upgrade;
 
-import java.io.IOException;
 import java.util.function.Supplier;
 
 import javax.servlet.ServletContext;
@@ -162,18 +161,18 @@ public class JettyRequestUpgradeStrategy implements RequestUpgradeStrategy, Life
 		boolean isUpgrade = this.factory.isUpgradeRequest(servletRequest, servletResponse);
 		Assert.isTrue(isUpgrade, "Not a WebSocket handshake");
 
-		try {
-			adapterHolder.set(new WebSocketHandlerContainer(adapter, subProtocol));
-			this.factory.acceptWebSocket(servletRequest, servletResponse);
-		}
-		catch (IOException ex) {
-			return Mono.error(ex);
-		}
-		finally {
-			adapterHolder.remove();
-		}
-
-		return Mono.empty();
+		// Trigger WebFlux preCommit actions and upgrade
+		return exchange.getResponse().setComplete()
+				.then(Mono.fromCallable(() -> {
+					try {
+						adapterHolder.set(new WebSocketHandlerContainer(adapter, subProtocol));
+						this.factory.acceptWebSocket(servletRequest, servletResponse);
+					}
+					finally {
+						adapterHolder.remove();
+					}
+					return null;
+				}));
 	}
 
 	private static HttpServletRequest getNativeRequest(ServerHttpRequest request) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
index f29c4f63564..8753d4bc324 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNettyRequestUpgradeStrategy.java
@@ -103,8 +103,13 @@ public class ReactorNettyRequestUpgradeStrategy implements RequestUpgradeStrateg
 		HttpServerResponse reactorResponse = getNativeResponse(response);
 		HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
 		NettyDataBufferFactory bufferFactory = (NettyDataBufferFactory) response.bufferFactory();
+
+		// Trigger WebFlux preCommit actions and upgrade
 		return response.setComplete()
-				.then(Mono.defer(() -> reactorResponse.sendWebsocket(subProtocol, this.maxFramePayloadLength, this.handlePing,
+				.then(Mono.defer(() -> reactorResponse.sendWebsocket(
+						subProtocol,
+						this.maxFramePayloadLength,
+						this.handlePing,
 						(in, out) -> {
 							ReactorNettyWebSocketSession session =
 									new ReactorNettyWebSocketSession(
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
index fb4ef36dd07..ad56c0370f1 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/TomcatRequestUpgradeStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,9 @@
 
 package org.springframework.web.reactive.socket.server.upgrade;
 
-import java.io.IOException;
 import java.util.Collections;
 import java.util.function.Supplier;
 
-import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.websocket.Endpoint;
@@ -147,15 +145,13 @@ public class TomcatRequestUpgradeStrategy implements RequestUpgradeStrategy {
 		config.setSubprotocols(subProtocol != null ?
 				Collections.singletonList(subProtocol) : Collections.emptyList());
 
-		try {
-			WsServerContainer container = getContainer(servletRequest);
-			container.doUpgrade(servletRequest, servletResponse, config, Collections.emptyMap());
-		}
-		catch (ServletException | IOException ex) {
-			return Mono.error(ex);
-		}
-
-		return Mono.empty();
+		// Trigger WebFlux preCommit actions and upgrade
+		return exchange.getResponse().setComplete()
+				.then(Mono.fromCallable(() -> {
+					WsServerContainer container = getContainer(servletRequest);
+					container.doUpgrade(servletRequest, servletResponse, config, Collections.emptyMap());
+					return null;
+				}));
 	}
 
 	private static HttpServletRequest getNativeRequest(ServerHttpRequest request) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
index 8307c8eed01..d57fb1b9481 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
@@ -64,6 +64,8 @@ public class UndertowRequestUpgradeStrategy implements RequestUpgradeStrategy {
 
 		HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
 		DataBufferFactory bufferFactory = exchange.getResponse().bufferFactory();
+
+		// Trigger WebFlux preCommit actions and upgrade
 		return exchange.getResponse().setComplete()
 				.then(Mono.fromCallable(() -> {
 					DefaultCallback callback = new DefaultCallback(handshakeInfo, handler, bufferFactory);