diff --git a/packages/router/src/create_url_tree.ts b/packages/router/src/create_url_tree.ts
index c454af5099..871fb4f0dc 100644
--- a/packages/router/src/create_url_tree.ts
+++ b/packages/router/src/create_url_tree.ts
@@ -147,14 +147,17 @@ function findStartingPosition(nav: Navigation, tree: UrlTree, route: ActivatedRo
     return new Position(tree.root, true, 0);
   }
 
+  const segmentGroup = route.snapshot._urlSegment;
+
   if (route.snapshot._lastPathIndex === -1) {
-    return new Position(route.snapshot._urlSegment, true, 0);
+    // Pathless ActivatedRoute has _lastPathIndex === -1 but should not process children
+    // see issue #26224
+    return new Position(segmentGroup, segmentGroup.segments.length === 0, 0);
   }
 
   const modifier = isMatrixParams(nav.commands[0]) ? 0 : 1;
   const index = route.snapshot._lastPathIndex + modifier;
-  return createPositionApplyingDoubleDots(
-      route.snapshot._urlSegment, index, nav.numberOfDoubleDots);
+  return createPositionApplyingDoubleDots(segmentGroup, index, nav.numberOfDoubleDots);
 }
 
 function createPositionApplyingDoubleDots(
diff --git a/packages/router/test/create_url_tree.spec.ts b/packages/router/test/create_url_tree.spec.ts
index 6b0e40a48e..487d65deea 100644
--- a/packages/router/test/create_url_tree.spec.ts
+++ b/packages/router/test/create_url_tree.spec.ts
@@ -233,6 +233,12 @@ describe('createUrlTree', () => {
       const t = create(p.root.children[PRIMARY_OUTLET], 1, p, [{outlets: {right: ['c']}}]);
       expect(serializer.serialize(t)).toEqual('/a/b/(right:c)');
     });
+
+    it('should support pathless route', () => {
+      const p = serializer.parse('/a');
+      const t = create(p.root.children[PRIMARY_OUTLET], -1, p, ['b']);
+      expect(serializer.serialize(t)).toEqual('/b');
+    });
   });
 
   it('should set fragment', () => {
@@ -260,8 +266,8 @@ function create(
     expect(segment).toBeDefined();
   }
   const s = new (ActivatedRouteSnapshot as any)(
-      [], <any>{}, <any>{}, '', <any>{}, PRIMARY_OUTLET, 'someComponent', null, <any>segment,
-      startIndex, <any>null);
+      segment.segments, <any>{}, <any>{}, '', <any>{}, PRIMARY_OUTLET, 'someComponent', null,
+      <any>segment, startIndex, <any>null);
   const a = new (ActivatedRoute as any)(
       new BehaviorSubject(null !), new BehaviorSubject(null !), new BehaviorSubject(null !),
       new BehaviorSubject(null !), new BehaviorSubject(null !), PRIMARY_OUTLET, 'someComponent', s);