diff --git a/Sources/DatadogSDKTesting/NetworkInstrumentation/DDNetworkInstrumentation.swift b/Sources/DatadogSDKTesting/NetworkInstrumentation/DDNetworkInstrumentation.swift
index 60ee710f..4bc28e50 100644
--- a/Sources/DatadogSDKTesting/NetworkInstrumentation/DDNetworkInstrumentation.swift
+++ b/Sources/DatadogSDKTesting/NetworkInstrumentation/DDNetworkInstrumentation.swift
@@ -178,21 +178,29 @@ class DDNetworkInstrumentation {
             }
             var originalIMP: IMP?
             let sessionTaskId = UUID().uuidString
-            
-            let block: @convention(block) (URLSession, AnyObject, @escaping (Any?, URLResponse?, Error?) -> Void) -> URLSessionTask = { session, argument, completion in
+
+            let block: @convention(block) (URLSession, AnyObject, ((Any?, URLResponse?, Error?) -> Void)? ) -> URLSessionTask = { session, argument, completion in
+
                 if let url = argument as? URL,
                    self.injectHeaders == true {
                     let request = URLRequest(url: url)
-                    
                     if selector == #selector(URLSession.dataTask(with:completionHandler:) as (URLSession) -> (URL, @escaping (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask) {
-                        return session.dataTask(with: request, completionHandler: completion)
+                        if let completion = completion {
+                            return session.dataTask(with: request, completionHandler: completion)
+                        } else {
+                            return session.dataTask(with: request)
+                        }
                     } else {
-                        return session.downloadTask(with: request, completionHandler: completion)
+                        if let completion = completion {
+                            return session.downloadTask(with: request, completionHandler: completion)
+                        } else {
+                            return session.downloadTask(with: request)
+                        }
                     }
                 }
                 
-                let castedIMP = unsafeBitCast(originalIMP, to: (@convention(c) (URLSession, Selector, Any, @escaping (Any?, URLResponse?, Error?) -> Void) -> URLSessionDataTask).self)
-                var task: URLSessionTask
+                let castedIMP = unsafeBitCast(originalIMP, to: (@convention(c) (URLSession, Selector, Any, ( (Any?, URLResponse?, Error?) -> Void)?) -> URLSessionDataTask).self)
+                var task: URLSessionTask!
                 
                 var completionBlock = completion
                 if objc_getAssociatedObject(argument, &idKey) == nil {
@@ -205,7 +213,11 @@ class DDNetworkInstrumentation {
                                 DDNetworkActivityLogger.log(response: response, dataOrFile: object, sessionTaskId: sessionTaskId)
                             }
                         }
-                        completion(object, response, error)
+                        if let completion = completion {
+                            completion(object, response, error)
+                        } else {
+                            (session.delegate as? URLSessionTaskDelegate)?.urlSession?(session, task: task, didCompleteWithError: error)
+                        }
                     }
                     completionBlock = completionWrapper
                 }
@@ -243,10 +255,11 @@ class DDNetworkInstrumentation {
             var originalIMP: IMP?
             let sessionTaskId = UUID().uuidString
             
-            let block: @convention(block) (URLSession, URLRequest, AnyObject, @escaping (Any?, URLResponse?, Error?) -> Void) -> URLSessionTask = { session, request, argument, completion in
-                
-                let castedIMP = unsafeBitCast(originalIMP, to: (@convention(c) (URLSession, Selector, URLRequest, AnyObject, @escaping (Any?, URLResponse?, Error?) -> Void) -> URLSessionDataTask).self)
+            let block: @convention(block) (URLSession, URLRequest, AnyObject, ( (Any?, URLResponse?, Error?) -> Void)?) -> URLSessionTask = { session, request, argument, completion in
                 
+                let castedIMP = unsafeBitCast(originalIMP, to: (@convention(c) (URLSession, Selector, URLRequest, AnyObject, ( (Any?, URLResponse?, Error?) -> Void)?) -> URLSessionDataTask).self)
+
+                var task: URLSessionTask!
                 var completionBlock = completion
                 if objc_getAssociatedObject(argument, &idKey) == nil {
                     let completionWrapper: (Any?, URLResponse?, Error?) -> Void = { object, response, error in
@@ -258,13 +271,17 @@ class DDNetworkInstrumentation {
                                 DDNetworkActivityLogger.log(response: response, dataOrFile: object, sessionTaskId: sessionTaskId)
                             }
                         }
-                        completion(object, response, error)
+                        if let completion = completion {
+                            completion(object, response, error)
+                        } else {
+                            (session.delegate as? URLSessionTaskDelegate)?.urlSession?(session, task: task, didCompleteWithError: error)
+                        }
                     }
                     completionBlock = completionWrapper
                 }
                 
                 let instrumentedRequest = self.instrumentedRequest(for: request)
-                let task = castedIMP(session, selector, instrumentedRequest, argument, completionBlock)
+                task = castedIMP(session, selector, instrumentedRequest, argument, completionBlock)
                 DDNetworkActivityLogger.log(request: instrumentedRequest, sessionTaskId: sessionTaskId)
                 
                 self.setIdKey(value: sessionTaskId, for: task)