diff --git a/Libraries/Network/RCTHTTPRequestHandler.mm b/Libraries/Network/RCTHTTPRequestHandler.mm
index 76131fa69f..9a555fab4e 100644
--- a/Libraries/Network/RCTHTTPRequestHandler.mm
+++ b/Libraries/Network/RCTHTTPRequestHandler.mm
@@ -29,12 +29,12 @@ RCT_EXPORT_MODULE()
 
 - (void)invalidate
 {
-  dispatch_async(self->_methodQueue, ^{
-    [self->_session invalidateAndCancel];
-    self->_session = nil;
-  });
+  std::lock_guard<std::mutex> lock(_mutex);
+  [self->_session invalidateAndCancel];
+  self->_session = nil;
 }
 
+// Needs to lock before call this method.
 - (BOOL)isValid
 {
   // if session == nil and delegates != nil, we've been invalidated
@@ -58,6 +58,7 @@ RCT_EXPORT_MODULE()
 - (NSURLSessionDataTask *)sendRequest:(NSURLRequest *)request
                          withDelegate:(id<RCTURLRequestDelegate>)delegate
 {
+  std::lock_guard<std::mutex> lock(_mutex);
   // Lazy setup
   if (!_session && [self isValid]) {
     // You can override default NSURLSession instance property allowsCellularAccess (default value YES)
@@ -83,19 +84,12 @@ RCT_EXPORT_MODULE()
                                              delegate:self
                                         delegateQueue:callbackQueue];
 
-    std::lock_guard<std::mutex> lock(_mutex);
     _delegates = [[NSMapTable alloc] initWithKeyOptions:NSPointerFunctionsStrongMemory
                                            valueOptions:NSPointerFunctionsStrongMemory
                                                capacity:0];
   }
-  __block NSURLSessionDataTask *task = nil;
-  dispatch_sync(self->_methodQueue, ^{
-    task = [self->_session dataTaskWithRequest:request];
-  });
-  {
-    std::lock_guard<std::mutex> lock(_mutex);
-    [_delegates setObject:delegate forKey:task];
-  }
+  NSURLSessionDataTask *task = [_session dataTaskWithRequest:request];
+  [_delegates setObject:delegate forKey:task];
   [task resume];
   return task;
 }