diff --git a/pandas_gbq/gbq.py b/pandas_gbq/gbq.py
index 061eacc6..fc3ac577 100644
--- a/pandas_gbq/gbq.py
+++ b/pandas_gbq/gbq.py
@@ -639,7 +639,7 @@ def _finalize_dtypes(
         "DATETIME": "datetime64[ns]",
         "TIMESTAMP": "datetime64[ns]",
     }
-    if tuple(int(part) for part in pandas.__version__.split()[:2]) >= (2, 1):
+    if tuple(int(part) for part in pandas.__version__.split(".")[:2]) >= (2, 1):
         # when pandas is 2.1.0 or later, default timestamp dtype is 'datetime64[us]'
         # and we should use 'datetime64[us]' instead of 'datetime64[ns]'
         dtype_map = {
diff --git a/tests/unit/test_gbq.py b/tests/unit/test_gbq.py
index 6b7dc11b..d2f71a95 100644
--- a/tests/unit/test_gbq.py
+++ b/tests/unit/test_gbq.py
@@ -114,7 +114,7 @@ def test__bqschema_to_nullsafe_dtypes(type_, expected):
 
 
 @pytest.mark.skipif(
-    tuple(int(part) for part in pandas.__version__.split()[:2]) < (2, 1),
+    tuple(int(part) for part in pandas.__version__.split(".")[:2]) < (2, 1),
     reason="requires pandas 2.1.0 or higher"
 )
 @pytest.mark.parametrize(