diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
index acf77aec9b3..ae0df2740e0 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
@@ -175,6 +175,8 @@ import org.elasticsearch.client.ml.job.config.JobUpdate;
 import org.elasticsearch.client.ml.job.config.MlFilter;
 import org.elasticsearch.client.ml.job.process.ModelSnapshot;
 import org.elasticsearch.client.ml.job.stats.JobStats;
+import org.elasticsearch.client.tasks.GetTaskRequest;
+import org.elasticsearch.client.tasks.GetTaskResponse;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.ByteSizeValue;
@@ -187,6 +189,7 @@ import org.elasticsearch.index.query.MatchAllQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.SearchHit;
+import org.elasticsearch.tasks.TaskId;
 import org.junit.After;
 
 import java.io.IOException;
@@ -198,6 +201,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
@@ -299,7 +303,18 @@ public class MachineLearningIT extends ESRestHighLevelClientTestCase {
         DeleteJobResponse response = execute(deleteJobRequest, machineLearningClient::deleteJob, machineLearningClient::deleteJobAsync);
 
         assertNull(response.getAcknowledged());
-        assertNotNull(response.getTask());
+
+        final TaskId taskId = response.getTask();
+        assertNotNull(taskId);
+
+        // When wait_for_completion=false the DeleteJobAction stored the task result in the .tasks index. In tests we need to wait
+        // for the delete job task to complete, otherwise the .tasks index could be created during the execution of a following test.
+        final GetTaskRequest taskRequest = new GetTaskRequest(taskId.getNodeId(), taskId.getId());
+        assertBusy(() -> {
+            Optional<GetTaskResponse> taskResponse = highLevelClient().tasks().get(taskRequest, RequestOptions.DEFAULT);
+            assertTrue(taskResponse.isPresent());
+            assertTrue(taskResponse.get().isCompleted());
+        }, 30L, TimeUnit.SECONDS);
     }
 
     public void testOpenJob() throws Exception {
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksIT.java
index d1e386bca0d..264437226bf 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/TasksIT.java
@@ -30,13 +30,14 @@ import org.elasticsearch.client.tasks.CancelTasksResponse;
 import org.elasticsearch.client.tasks.GetTaskRequest;
 import org.elasticsearch.client.tasks.GetTaskResponse;
 import org.elasticsearch.client.tasks.TaskId;
+import org.elasticsearch.client.tasks.TaskSubmissionResponse;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.rest.RestStatus;
 
 import java.io.IOException;
 import java.util.Collections;
-import java.util.Map;
 import java.util.Optional;
 
 import static java.util.Collections.emptyList;
@@ -70,11 +71,10 @@ public class TasksIT extends ESRestHighLevelClientTestCase {
         }
         assertTrue("List tasks were not found", listTasksFound);
     }
-    
+
     public void testGetValidTask() throws Exception {
 
         // Run a Reindex to create a task
-
         final String sourceIndex = "source1";
         final String destinationIndex = "dest";
         Settings settings = Settings.builder().put("number_of_shards", 1).put("number_of_replicas", 0).build();
@@ -85,34 +85,19 @@ public class TasksIT extends ESRestHighLevelClientTestCase {
                 .add(new IndexRequest(sourceIndex).id("2").source(Collections.singletonMap("foo2", "bar2"), XContentType.JSON))
                 .setRefreshPolicy(RefreshPolicy.IMMEDIATE);
         assertEquals(RestStatus.OK, highLevelClient().bulk(bulkRequest, RequestOptions.DEFAULT).status());
-        
-        // (need to use low level client because currently high level client
-        // doesn't support async return of task id - needs
-        // https://github.com/elastic/elasticsearch/pull/35202 )
-        RestClient lowClient = highLevelClient().getLowLevelClient();
-        Request request = new Request("POST", "_reindex");
-        request.addParameter("wait_for_completion", "false");
-        request.setJsonEntity(
-            "{"
-                + "  \"source\": {\n"
-                + "    \"index\": \"source1\"\n"
-                + "  },\n"
-                + "  \"dest\": {\n"
-                + "    \"index\": \"dest\"\n"
-                + "  }"
-                + "}"
-        );
-        Response response = lowClient.performRequest(request);
-        Map<String, Object> map = entityAsMap(response);
-        Object taskId = map.get("task");
+
+        final ReindexRequest reindexRequest = new ReindexRequest().setSourceIndices(sourceIndex).setDestIndex(destinationIndex);
+        final TaskSubmissionResponse taskSubmissionResponse = highLevelClient().submitReindexTask(reindexRequest, RequestOptions.DEFAULT);
+
+        final String taskId = taskSubmissionResponse.getTask();
         assertNotNull(taskId);
 
-        TaskId childTaskId = new TaskId(taskId.toString());
+        TaskId childTaskId = new TaskId(taskId);
         GetTaskRequest gtr = new GetTaskRequest(childTaskId.getNodeId(), childTaskId.getId());
         gtr.setWaitForCompletion(randomBoolean());
         Optional<GetTaskResponse> getTaskResponse = execute(gtr, highLevelClient().tasks()::get, highLevelClient().tasks()::getAsync);
         assertTrue(getTaskResponse.isPresent());
-        GetTaskResponse taskResponse = getTaskResponse.get();        
+        GetTaskResponse taskResponse = getTaskResponse.get();
         if (gtr.getWaitForCompletion()) {
             assertTrue(taskResponse.isCompleted());
         }
@@ -121,15 +106,15 @@ public class TasksIT extends ESRestHighLevelClientTestCase {
         assertEquals("reindex from [source1] to [dest][_doc]", info.getDescription());
         assertEquals("indices:data/write/reindex", info.getAction());
         if (taskResponse.isCompleted() == false) {
-            assertBusy(checkTaskCompletionStatus(client(), taskId.toString()));
+            assertBusy(checkTaskCompletionStatus(client(), taskId));
         }
-    }    
-    
+    }
+
     public void testGetInvalidTask() throws IOException {
         // Check 404s are returned as empty Optionals
-        GetTaskRequest gtr = new GetTaskRequest("doesNotExistNodeName", 123);                
+        GetTaskRequest gtr = new GetTaskRequest("doesNotExistNodeName", 123);
         Optional<GetTaskResponse> getTaskResponse = execute(gtr, highLevelClient().tasks()::get, highLevelClient().tasks()::getAsync);
-        assertFalse(getTaskResponse.isPresent());               
+        assertFalse(getTaskResponse.isPresent());
     }
 
     public void testCancelTasks() throws IOException {