diff --git a/dvc/repo/experiments/__init__.py b/dvc/repo/experiments/__init__.py
index fbfa93c443..2aea830820 100644
--- a/dvc/repo/experiments/__init__.py
+++ b/dvc/repo/experiments/__init__.py
@@ -312,31 +312,18 @@ def _unpack_args(self, tree=None):
 
     def _update_params(self, params: dict):
         """Update experiment params files with the specified values."""
+        from benedict import benedict
+
         from dvc.utils.serialize import MODIFIERS
 
         logger.debug("Using experiment params '%s'", params)
 
-        # recursive dict update
-        def _update(dict_, other):
-            for key, value in other.items():
-                if isinstance(dict_, list) and key.isdigit():
-                    key = int(key)
-                if isinstance(value, Mapping):
-                    if isinstance(dict_, list):
-                        fallback_value = dict_[key]
-                    else:
-                        fallback_value = dict_.get(key, {})
-                    dict_[key] = _update(fallback_value, value)
-                else:
-                    dict_[key] = value
-            return dict_
-
         for params_fname in params:
             path = PathInfo(self.exp_dvc.root_dir) / params_fname
             suffix = path.suffix.lower()
             modify_data = MODIFIERS[suffix]
             with modify_data(path, tree=self.exp_dvc.tree) as data:
-                _update(data, params[params_fname])
+                benedict(data).merge(params[params_fname], overwrite=True)
 
         # Force params file changes to be staged in git
         # Otherwise in certain situations the changes to params file may be
diff --git a/dvc/repo/experiments/run.py b/dvc/repo/experiments/run.py
index 112ec8aebf..92a6f80c8b 100644
--- a/dvc/repo/experiments/run.py
+++ b/dvc/repo/experiments/run.py
@@ -12,7 +12,6 @@ def _parse_params(path_params: Iterable):
     from ruamel.yaml import YAMLError
 
     from dvc.dependency.param import ParamsDependency
-    from dvc.utils.flatten import unflatten
     from dvc.utils.serialize import loads_yaml
 
     ret = {}
@@ -31,7 +30,7 @@ def _parse_params(path_params: Iterable):
                 )
         if not path:
             path = ParamsDependency.DEFAULT_PARAMS_FILE
-        ret[path] = unflatten(params)
+        ret[path] = params
     return ret
 
 
diff --git a/setup.py b/setup.py
index aac5a8bf97..d698315acd 100644
--- a/setup.py
+++ b/setup.py
@@ -82,6 +82,7 @@ def run(self):
     "shtab>=1.3.2,<2",
     "rich>=3.0.5",
     "dictdiffer>=0.8.1",
+    "python-benedict>=0.21.1",
 ]
 
 
diff --git a/tests/func/experiments/test_experiments.py b/tests/func/experiments/test_experiments.py
index 49578a09d6..e8ba0d6f71 100644
--- a/tests/func/experiments/test_experiments.py
+++ b/tests/func/experiments/test_experiments.py
@@ -66,27 +66,45 @@ def test_update_with_pull(tmp_dir, scm, dvc, exp_stage, mocker):
 
 
 @pytest.mark.parametrize(
-    "change, expected",
+    "changes, expected",
     [
-        ["foo.1.baz=3", "foo: [bar: 1, baz: 3]"],
-        ["foo.0=bar", "foo: [bar, baz: 2]"],
-        ["foo.1=- baz\n- goo", "foo: [bar: 1, [baz, goo]]"],
+        [["foo=baz"], "{foo: baz, goo: {bag: 3}, lorem: false}"],
+        [["foo=baz,goo=bar"], "{foo: baz, goo: bar, lorem: false}"],
+        [
+            ["goo.bag=4"],
+            "{foo: [bar: 1, baz: 2], goo: {bag: 4}, lorem: false}",
+        ],
+        [["foo[0]=bar"], "{foo: [bar, baz: 2], goo: {bag: 3}, lorem: false}"],
+        [
+            ["foo[1].baz=3"],
+            "{foo: [bar: 1, baz: 3], goo: {bag: 3}, lorem: false}",
+        ],
+        [
+            ["foo[1]=- baz\n- goo"],
+            "{foo: [bar: 1, [baz, goo]], goo: {bag: 3}, lorem: false}",
+        ],
+        [
+            ["lorem.ipsum=3"],
+            "{foo: [bar: 1, baz: 2], goo: {bag: 3}, lorem: {ipsum: 3}}",
+        ],
     ],
 )
-def test_modify_list_param(tmp_dir, scm, dvc, mocker, change, expected):
+def test_modify_params(tmp_dir, scm, dvc, mocker, changes, expected):
     tmp_dir.gen("copy.py", COPY_SCRIPT)
-    tmp_dir.gen("params.yaml", "foo: [bar: 1, baz: 2]")
+    tmp_dir.gen(
+        "params.yaml", "{foo: [bar: 1, baz: 2], goo: {bag: 3}, lorem: false}"
+    )
     stage = dvc.run(
         cmd="python copy.py params.yaml metrics.yaml",
         metrics_no_cache=["metrics.yaml"],
-        params=["foo"],
+        params=["foo", "goo", "lorem"],
         name="copy-file",
     )
     scm.add(["dvc.yaml", "dvc.lock", "copy.py", "params.yaml", "metrics.yaml"])
     scm.commit("init")
 
     new_mock = mocker.spy(dvc.experiments, "new")
-    dvc.experiments.run(stage.addressing, params=[change])
+    dvc.experiments.run(stage.addressing, params=changes)
 
     new_mock.assert_called_once()
     assert (