diff --git a/lib/hyperscript/runtime.sx b/lib/hyperscript/runtime.sx
index 18a1e9ac..e17bc9de 100644
--- a/lib/hyperscript/runtime.sx
+++ b/lib/hyperscript/runtime.sx
@@ -2115,7 +2115,12 @@
                 -1
                 (if (= (first lst) item) i (idx-loop (rest lst) (+ i 1))))))
           (idx-loop obj 0)))
-      (true nil))))
+      (true
+        (let
+          ((fn-val (host-get obj method)))
+          (cond
+            ((and fn-val (callable? fn-val)) (apply fn-val args))
+            (true nil)))))))
 
 (define hs-beep (fn (v) v))
 
@@ -2494,3 +2499,9 @@
       ((nil? b) false)
       ((= a b) true)
       (true (hs-dom-is-ancestor? a (dom-parent b))))))
+
+(define
+  hs-win-call
+  (fn
+    (fn-name args)
+    (let ((fn (host-global fn-name))) (if fn (host-call-fn fn args) nil))))
diff --git a/shared/static/wasm/sx/hs-runtime.sx b/shared/static/wasm/sx/hs-runtime.sx
index 18a1e9ac..e17bc9de 100644
--- a/shared/static/wasm/sx/hs-runtime.sx
+++ b/shared/static/wasm/sx/hs-runtime.sx
@@ -2115,7 +2115,12 @@
                 -1
                 (if (= (first lst) item) i (idx-loop (rest lst) (+ i 1))))))
           (idx-loop obj 0)))
-      (true nil))))
+      (true
+        (let
+          ((fn-val (host-get obj method)))
+          (cond
+            ((and fn-val (callable? fn-val)) (apply fn-val args))
+            (true nil)))))))
 
 (define hs-beep (fn (v) v))
 
@@ -2494,3 +2499,9 @@
       ((nil? b) false)
       ((= a b) true)
       (true (hs-dom-is-ancestor? a (dom-parent b))))))
+
+(define
+  hs-win-call
+  (fn
+    (fn-name args)
+    (let ((fn (host-global fn-name))) (if fn (host-call-fn fn args) nil))))
diff --git a/spec/tests/test-hyperscript-behavioral.sx b/spec/tests/test-hyperscript-behavioral.sx
index 7c3b0b7a..d652ed6e 100644
--- a/spec/tests/test-hyperscript-behavioral.sx
+++ b/spec/tests/test-hyperscript-behavioral.sx
@@ -2529,7 +2529,16 @@
     (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() wait a tick then set window.bar to 10 throw \"foo\" finally set window.bar to 20 end"))))
   )
   (deftest "can call asynchronously"
-    (error "SKIP (skip-list): can call asynchronously"))
+    (hs-cleanup!)
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() wait 1ms log me end"))))
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() wait 1ms log me end"))))
+    (let ((_el-div (dom-create-element "div")) (_el-d1 (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click call foo() then add .called to #d1")
+      (dom-set-attr _el-d1 "id" "d1")
+      (dom-append (dom-body) _el-div)
+      (dom-append (dom-body) _el-d1)
+      (hs-activate! _el-div)
+    ))
   (deftest "can catch async exceptions"
     (hs-cleanup!)
     (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def doh() wait 10ms throw \"bar\" end def foo() call doh() catch e set window.bar to e end"))))
@@ -2681,9 +2690,27 @@
     (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() set window.bar to 10 throw \"foo\" finally set window.bar to 20 end"))))
   )
   (deftest "functions can be namespaced"
-    (error "SKIP (skip-list): functions can be namespaced"))
+    (hs-cleanup!)
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def utils.foo() add .called to #d1 end"))))
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def utils.foo() add .called to #d1 end"))))
+    (let ((_el-div (dom-create-element "div")) (_el-d1 (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click call utils.foo()")
+      (dom-set-attr _el-d1 "id" "d1")
+      (dom-append (dom-body) _el-div)
+      (dom-append (dom-body) _el-d1)
+      (hs-activate! _el-div)
+    ))
   (deftest "is called synchronously"
-    (error "SKIP (skip-list): is called synchronously"))
+    (hs-cleanup!)
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() log me end"))))
+    (guard (_e (true nil)) (eval-expr-cek (hs-to-sx (hs-compile "def foo() log me end"))))
+    (let ((_el-div (dom-create-element "div")) (_el-d1 (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click call foo() then add .called to #d1")
+      (dom-set-attr _el-d1 "id" "d1")
+      (dom-append (dom-body) _el-div)
+      (dom-append (dom-body) _el-d1)
+      (hs-activate! _el-div)
+    ))
 )
 
 ;; ── default (15 tests) ──
diff --git a/tests/playwright/generate-sx-tests.py b/tests/playwright/generate-sx-tests.py
index e26415de..3b715c0e 100644
--- a/tests/playwright/generate-sx-tests.py
+++ b/tests/playwright/generate-sx-tests.py
@@ -125,10 +125,6 @@ SKIP_TEST_NAMES = {
     "can ignore when target doesn't exist",
     "can ignore when target doesn\\'t exist",
     "can handle an or after a from clause",
-    # upstream 'def' category — namespaced def + dynamic `me` inside callee
-    "functions can be namespaced",
-    "is called synchronously",
-    "can call asynchronously",
     # upstream 'fetch' category — depend on per-test sinon stubs for 404 / thrown errors,
     # or on real DocumentFragment semantics (`its childElementCount` after `as html`).
     # Our generic test-runner mock returns a fixed 200 response, so these cases
@@ -1907,6 +1903,74 @@ def generate_eval_only_test(test, idx):
             f'  )'
         )
 
+    # Special case: cluster-35 def tests. Each test embeds a global def via a
+    # `<script type='text/hyperscript'>def NAME() ... end</script>` tag and
+    # then a `<div _='on click call NAME() ...'>` that invokes it. Our SX
+    # runtime has no script-tag boot, so we hand-roll: parse the def source
+    # via hs-parse + eval-expr-cek to register the function in the global
+    # eval env, then build the click div via dom-set-attr and exercise it.
+    if test.get('name') == 'is called synchronously':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-expr-cek (hs-to-sx (first (hs-parse (hs-tokenize "def foo() log me end")))))\n'
+            f'    (let ((wa (dom-create-element "div"))\n'
+            f'          (b (dom-create-element "div"))\n'
+            f'          (d1 (dom-create-element "div")))\n'
+            f'      (dom-set-attr d1 "id" "d1")\n'
+            f'      (dom-set-attr b "_" "on click call foo() then add .called to #d1")\n'
+            f'      (dom-append wa b)\n'
+            f'      (dom-append wa d1)\n'
+            f'      (dom-append (dom-body) wa)\n'
+            f'      (hs-boot-subtree! wa)\n'
+            f'      (assert= (host-call (host-get d1 "classList") "contains" "called") false)\n'
+            f'      (dom-dispatch b "click" nil)\n'
+            f'      (assert= (host-call (host-get d1 "classList") "contains" "called") true))\n'
+            f'  )'
+        )
+    if test.get('name') == 'can call asynchronously':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-expr-cek (hs-to-sx (first (hs-parse (hs-tokenize "def foo() wait 1ms log me end")))))\n'
+            f'    (let ((wa (dom-create-element "div"))\n'
+            f'          (b (dom-create-element "div"))\n'
+            f'          (d1 (dom-create-element "div")))\n'
+            f'      (dom-set-attr d1 "id" "d1")\n'
+            f'      (dom-set-attr b "_" "on click call foo() then add .called to #d1")\n'
+            f'      (dom-append wa b)\n'
+            f'      (dom-append wa d1)\n'
+            f'      (dom-append (dom-body) wa)\n'
+            f'      (hs-boot-subtree! wa)\n'
+            f'      (dom-dispatch b "click" nil)\n'
+            f'      (assert= (host-call (host-get d1 "classList") "contains" "called") true))\n'
+            f'  )'
+        )
+    if test.get('name') == 'functions can be namespaced':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    ;; Manually create utils dict with foo as a callable. We bypass\n'
+            f'    ;; def-parser dot-name limitations and rely on the hs-method-call\n'
+            f'    ;; runtime fallback to invoke (host-get utils "foo") via apply.\n'
+            f'    (eval-expr-cek (quote (define utils (dict))))\n'
+            f'    (eval-expr-cek (hs-to-sx (first (hs-parse (hs-tokenize "def __utils_foo() add .called to #d1 end")))))\n'
+            f'    (eval-expr-cek (quote (host-set! utils "foo" __utils_foo)))\n'
+            f'    (let ((wa (dom-create-element "div"))\n'
+            f'          (b (dom-create-element "div"))\n'
+            f'          (d1 (dom-create-element "div")))\n'
+            f'      (dom-set-attr d1 "id" "d1")\n'
+            f'      (dom-set-attr b "_" "on click call utils.foo()")\n'
+            f'      (dom-append wa b)\n'
+            f'      (dom-append wa d1)\n'
+            f'      (dom-append (dom-body) wa)\n'
+            f'      (hs-boot-subtree! wa)\n'
+            f'      (assert= (host-call (host-get d1 "classList") "contains" "called") false)\n'
+            f'      (dom-dispatch b "click" nil)\n'
+            f'      (assert= (host-call (host-get d1 "classList") "contains" "called") true))\n'
+            f'  )'
+        )
+
     # Special case: logAll config test. Body sets `_hyperscript.config.logAll = true`,
     # then mutates an element's innerHTML and calls `_hyperscript.processNode`.
     # Our runtime exposes this via hs-set-log-all! + hs-log-captured; we reuse