diff --git a/src/retsu/core.py b/src/retsu/core.py
index 2c5c864..cc83c11 100644
--- a/src/retsu/core.py
+++ b/src/retsu/core.py
@@ -226,47 +226,38 @@ def __init__(
     def acquire(self, task_id: str) -> bool:
         """Try to acquire a semaphore slot and ensure FIFO order."""
         task_bid = task_id.encode("utf8")
-        # logging.info(
-        #     f"[Semaphore] Task {task_id} is attempting to acquire a slot."
-        # )
-        # Add task to queue
         queue_name = f"{self.key}_queue"
+
+        # Add task to the queue
         self.redis_client.rpush(queue_name, task_id)
 
         while True:
-            # Get the current task at the front of the queue
-            current_task_id_tmp = self.redis_client.lindex(queue_name, 0)
-
-            if current_task_id_tmp is None:
-                time.sleep(0.1)  # Polling interval to wait for the slot
-                continue
-
-            current_task_id = cast(bytes, current_task_id_tmp)
-
-            # logging.info(
-            #     f"[Semaphore] Current task at front: {current_task_id}"
-            # )
-
-            # If the current task is this one, check if a semaphore slot is
-            # available
-            if current_task_id != task_bid:
-                time.sleep(0.1)  # Polling interval to wait for the slot
-                continue
-
-            count_tmp = self.redis_client.get(self.key)
-            current_count = int(cast(bytes, count_tmp) or 0)
-            # logging.info(f"[Semaphore] Current count: {current_count}")
-
-            if current_count < self.max_concurrent_tasks:
-                # logging.info(f"[Semaphore] Task {task_id} acquired a slot.")
+            # Get the list of current tasks in the queue
+            queue_tasks = self.redis_client.lrange(queue_name, 0, -1)
+            count_tmp = cast(bytes, self.redis_client.get(self.key) or b"0")
+            current_count = int(count_tmp)
+
+            # Check if the task is in the first `max_concurrent_tasks`
+            # in the queue
+            # mypy: Item "Awaitable[List[Any]]" of
+            #    "Union[Awaitable[List[Any]], List[Any]]"
+            #    has no attribute "index"
+            task_position = queue_tasks.index(task_bid)  # type: ignore
+
+            if (
+                task_position < self.max_concurrent_tasks
+                and current_count < self.max_concurrent_tasks
+            ):
+                # If a slot is available and the task is within the
+                # allowed concurrent limit
                 self.redis_client.incr(self.key)
                 return True
 
-            # keep waiting until any slot is available
-            time.sleep(0.01)
+            # If no slot is available or task is not in the allowed
+            # concurrent tasks, keep waiting
+            time.sleep(0.1)
 
     def release(self) -> None:
         """Release a semaphore slot and remove the task from the queue."""
-        # logging.info(f"[Semaphore] Releasing a slot.")
         self.redis_client.decr(self.key)
         self.redis_client.lpop(f"{self.key}_queue")
diff --git a/tests/test_task_celery_wrapup.py b/tests/test_task_celery_wrapup.py
index 348633e..34c2ce5 100644
--- a/tests/test_task_celery_wrapup.py
+++ b/tests/test_task_celery_wrapup.py
@@ -6,39 +6,43 @@
 
 from celery import Task
 
-from .celery_tasks import task_sequence_get_time
+from .celery_tasks import (
+    task_random_get_time,
+    task_sequence_get_time,
+)
 
-# def test_task_random_get_time() -> None:
-#     """Test task_random_get_time."""
-#     results: dict[int, float] = {}
-#     tasks: list[Task] = []
-#     start_time = time.time()
 
-#     for i in range(10):
-#         task_promise = task_random_get_time.s(
-#             request_id=i, start_time=start_time
-#         )
-#         tasks.append(task_promise.apply_async())
+def test_task_random_get_time() -> None:
+    """Test task_random_get_time."""
+    results: dict[int, float] = {}
+    tasks: list[Task] = []
+    start_time = time.time()
 
-#     for i in range(10):
-#         task = tasks[i]
-#         task_id, result = task.get(timeout=10)
-#         assert i == task_id
-#         results[task_id] = result
+    for i in range(10):
+        task_promise = task_random_get_time.s(
+            request_id=i, start_time=start_time
+        )
+        tasks.append(task_promise.apply_async())
 
-#     previous_time = results[0]
-#     previous_id = 0
-#     tol = 0.2
-#     for i in range(10):
-#         current_time = results[i]
-#         diff = abs(current_time - previous_time)
-#         # print(
-#         #     f"task {previous_id}-{i}, diff: {diff}, "
-#         #     f"expected: {diff_expected}"
-#         # )
-#         assert diff - tol < 5, f"[EE] Task {previous_id}-{i}"
-#         previous_time = current_time
-#         previous_id = i
+    for i in range(10):
+        task = tasks[i]
+        task_id, result = task.get(timeout=10)
+        assert i == task_id
+        results[task_id] = result
+
+    previous_time = results[0]
+    previous_id = 0
+    tol = 0.2
+    for i in range(10):
+        current_time = results[i]
+        diff = abs(current_time - previous_time)
+        # print(
+        #     f"task {previous_id}-{i}, diff: {diff}, "
+        #     f"expected: {diff_expected}"
+        # )
+        assert diff - tol < 5, f"[EE] Task {previous_id}-{i}"
+        previous_time = current_time
+        previous_id = i
 
 
 def test_task_sequence_get_time() -> None:
@@ -79,10 +83,10 @@ def test_task_sequence_get_time() -> None:
         current_time = results[i]
         diff = current_time - previous_time
         diff_expected = diffs[i]
-        print(
-            f"task {previous_id}-{i}, diff: {diff}, "
-            f"expected: {diff_expected}"
-        )
+        # print(
+        #     f"task {previous_id}-{i}, diff: {diff}, "
+        #     f"expected: {diff_expected}"
+        # )
         assert diff >= diff_expected - tol, f"[EE] Task {previous_id}-{i}"
         assert diff <= diff_expected + tol, f"[EE] Task {previous_id}-{i}"
         previous_time = current_time