diff --git a/addons/mail/static/src/components/autocomplete_input/autocomplete_input.js b/addons/mail/static/src/components/autocomplete_input/autocomplete_input.js
index e9bb5286ee2..c80bbafc4c7 100644
--- a/addons/mail/static/src/components/autocomplete_input/autocomplete_input.js
+++ b/addons/mail/static/src/components/autocomplete_input/autocomplete_input.js
@@ -11,6 +11,7 @@ class AutocompleteInput extends Component {
         }
 
         let args = {
+            autoFocus: true,
             select: (ev, ui) => this._onAutocompleteSelect(ev, ui),
             source: (req, res) => this._onAutocompleteSource(req, res),
             focus: ev => this._onAutocompleteFocus(ev),
diff --git a/addons/mail/static/src/components/chat_window_manager/chat_window_manager_tests.js b/addons/mail/static/src/components/chat_window_manager/chat_window_manager_tests.js
index d8c62e31a87..e76ff23fc38 100644
--- a/addons/mail/static/src/components/chat_window_manager/chat_window_manager_tests.js
+++ b/addons/mail/static/src/components/chat_window_manager/chat_window_manager_tests.js
@@ -380,6 +380,48 @@ QUnit.test('open chat from "new message" chat window should open chat in place o
     );
 });
 
+QUnit.test('new message autocomplete should automatically select first result', async function (assert) {
+    assert.expect(1);
+
+    this.data['res.partner'].records.push({ id: 131, name: "Partner 131" });
+    this.data['res.users'].records.push({ partner_id: 131 });
+    const imSearchDef = makeDeferred();
+    await this.start({
+        async mockRPC(route, args) {
+            const res = await this._super(...arguments);
+            if (args.method === 'im_search') {
+                imSearchDef.resolve();
+            }
+            return res;
+        },
+    });
+
+    // open "new message" chat window
+    await afterNextRender(() =>
+        document.querySelector(`.o_MessagingMenu_toggler`).click()
+    );
+    await afterNextRender(() =>
+        document.querySelector(`.o_MessagingMenu_newMessageButton`).click()
+    );
+
+    // search for a user in "new message" autocomplete
+    document.execCommand('insertText', false, "131");
+    document.querySelector(`.o_ChatWindow_newMessageFormInput`)
+        .dispatchEvent(new window.KeyboardEvent('keydown'));
+    document.querySelector(`.o_ChatWindow_newMessageFormInput`)
+        .dispatchEvent(new window.KeyboardEvent('keyup'));
+    // Wait for search RPC to be resolved. The following await lines are
+    // necessary because autocomplete is an external lib therefore it is not
+    // possible to use `afterNextRender`.
+    await imSearchDef;
+    await nextAnimationFrame();
+    assert.hasClass(
+        document.querySelector('.ui-autocomplete .ui-menu-item a'),
+        'ui-state-active',
+        "first autocomplete result should be automatically selected",
+    );
+});
+
 QUnit.test('chat window: basic rendering', async function (assert) {
     assert.expect(11);