diff --git a/apps/start/src/components/onboarding/install-snippets.ts b/apps/start/src/components/onboarding/install-snippets.ts
index 5fe5d38ad..89e4821a6 100644
--- a/apps/start/src/components/onboarding/install-snippets.ts
+++ b/apps/start/src/components/onboarding/install-snippets.ts
@@ -25,7 +25,7 @@ const apiUrlLine = (context: SnippetContext, indent: string) =>
 
 export function scriptTagSnippet(context: SnippetContext): string {
   return `<script>
-  window.op=window.op||function(){var n=[];return new Proxy(function(){arguments.length&&n.push([].slice.call(arguments))},{get:function(t,r){return"q"===r?n:function(){n.push([r].concat([].slice.call(arguments)))}} ,has:function(t,r){return"q"===r}}) }();
+  window.op=window.op||function(){var n=[];return new Proxy(function(){arguments.length&&n.push([].slice.call(arguments))},{get:function(t,r){return"q"===r?n:"call"===r||"apply"===r||"bind"===r?t[r]:function(){n.push([r].concat([].slice.call(arguments)))}} ,has:function(t,r){return"q"===r}}) }();
   window.op('init', {${apiUrlLine(context, '    ')}
     clientId: '${context.clientId}',
     trackScreenViews: true,
diff --git a/apps/testbed/e2e/sdk.spec.ts b/apps/testbed/e2e/sdk.spec.ts
index 687c39cec..92e222804 100644
--- a/apps/testbed/e2e/sdk.spec.ts
+++ b/apps/testbed/e2e/sdk.spec.ts
@@ -3,6 +3,12 @@ import { TESTBED_URL } from '../playwright.config';
 import { type StoredEvent, waitForEvents } from './clickhouse';
 
 const OUTGOING_LINK = 'https://openpanel.dev/';
+const SCRIPT_TAG_EVENTS = [
+  'op_call_before_load',
+  'op_apply_before_load',
+  'op_call_after_load',
+  'op_apply_after_load',
+];
 
 function byName(events: StoredEvent[], name: string) {
   return events.filter((event) => event.name === name);
@@ -52,3 +58,39 @@ test('the web SDK stores screen views, custom and automatic events with their pa
   expect(linkOut?.path).toBe('/product/p1');
   expect(linkOut?.properties).toMatchObject({ href: OUTGOING_LINK });
 });
+
+test('the script tag keeps events sent through window.op.call, as Turbopack compiles window.op?.()', async ({
+  page,
+}) => {
+  const since = new Date();
+  const pageErrors: Error[] = [];
+  page.on('pageerror', (error) => pageErrors.push(error));
+
+  await page.goto('/script-tag.html');
+  await page.waitForFunction(() => 'loadTracker' in window);
+
+  await page.evaluate(() => {
+    window.op.call(window, 'track', 'op_call_before_load', { via: 'call' });
+    window.op.apply(window, ['track', 'op_apply_before_load']);
+  });
+  await page.evaluate(() => window.loadTracker());
+  await page.evaluate(() => {
+    window.op.call(window, 'track', 'op_call_after_load', { via: 'call' });
+    window.op.apply(window, ['track', 'op_apply_after_load']);
+  });
+
+  const events = await waitForEvents(TESTBED_URL, since, (stored) =>
+    SCRIPT_TAG_EVENTS.every((name) => byName(stored, name).length >= 1)
+  );
+
+  expect(pageErrors).toEqual([]);
+  for (const name of SCRIPT_TAG_EVENTS) {
+    expect(byName(events, name)[0]?.path).toBe('/script-tag.html');
+  }
+  expect(byName(events, 'op_call_before_load')[0]?.properties).toMatchObject({
+    via: 'call',
+  });
+  expect(byName(events, 'op_call_after_load')[0]?.properties).toMatchObject({
+    via: 'call',
+  });
+});
diff --git a/apps/testbed/script-tag.html b/apps/testbed/script-tag.html
new file mode 100644
index 000000000..8b3043fdc
--- /dev/null
+++ b/apps/testbed/script-tag.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <title>Script tag | OpenPanel SDK</title>
+  </head>
+  <body>
+    <script type="module" src="/src/script-tag.ts"></script>
+  </body>
+</html>
diff --git a/apps/testbed/src/script-tag.ts b/apps/testbed/src/script-tag.ts
new file mode 100644
index 000000000..9b216bfee
--- /dev/null
+++ b/apps/testbed/src/script-tag.ts
@@ -0,0 +1,21 @@
+import { getInitSnippet } from '@openpanel/web';
+
+declare global {
+  interface Window {
+    loadTracker: () => Promise<unknown>;
+  }
+}
+
+// A customer site's two script tags, taken from source: public/op1.js is the
+// last released build, not the code under test. The spec decides when the
+// second one "arrives" so it can call window.op on both sides of it.
+const snippet = document.createElement('script');
+snippet.textContent = getInitSnippet();
+document.head.append(snippet);
+
+window.op('init', {
+  clientId: import.meta.env.VITE_OPENPANEL_CLIENT_ID ?? 'testbed-client',
+  apiUrl: import.meta.env.VITE_OPENPANEL_API_URL ?? 'http://localhost:3333',
+});
+
+window.loadTracker = () => import('@openpanel/web/src/tracker');
diff --git a/packages/sdks/web/src/init-snippet.ts b/packages/sdks/web/src/init-snippet.ts
index 81388180d..07802a596 100644
--- a/packages/sdks/web/src/init-snippet.ts
+++ b/packages/sdks/web/src/init-snippet.ts
@@ -6,10 +6,13 @@
 //       q.push(Array.prototype.slice.call(arguments));
 //     }
 //   }, {
-//     get: function(_, prop) {
+//     get: function(target, prop) {
 //       if (prop === 'q') {
 //         return q;
 //       }
+//       if (prop === 'call' || prop === 'apply' || prop === 'bind') {
+//         return target[prop];
+//       }
 //       return function() {
 //         q.push([prop].concat(Array.prototype.slice.call(arguments)));
 //       };
@@ -19,5 +22,5 @@
 // })();
 
 export function getInitSnippet(): string {
-  return `window.op=window.op||function(){var n=[];return new Proxy(function(){arguments.length&&n.push([].slice.call(arguments))},{get:function(t,r){return"q"===r?n:function(){n.push([r].concat([].slice.call(arguments)))}} ,has:function(t,r){return"q"===r}}) }();`;
+  return `window.op=window.op||function(){var n=[];return new Proxy(function(){arguments.length&&n.push([].slice.call(arguments))},{get:function(t,r){return"q"===r?n:"call"===r||"apply"===r||"bind"===r?t[r]:function(){n.push([r].concat([].slice.call(arguments)))}} ,has:function(t,r){return"q"===r}}) }();`;
 }
diff --git a/packages/sdks/web/src/tracker.test.ts b/packages/sdks/web/src/tracker.test.ts
new file mode 100644
index 000000000..505ea0ca1
--- /dev/null
+++ b/packages/sdks/web/src/tracker.test.ts
@@ -0,0 +1,117 @@
+import { afterEach, beforeEach, describe, expect, test } from 'bun:test';
+import type { TrackHandlerPayload } from '@openpanel/sdk';
+import { JSDOM } from 'jsdom';
+import { getInitSnippet } from './init-snippet';
+
+const PAGE_URL = 'https://example.com/pricing';
+const DOM_GLOBALS = [
+  'window',
+  'document',
+  'history',
+  'sessionStorage',
+  'HTMLElement',
+] as const;
+
+let dom: JSDOM;
+let sent: TrackHandlerPayload[];
+let trackerLoads = 0;
+
+function installSnippet() {
+  dom.window.eval(getInitSnippet());
+  dom.window.op('init', {
+    clientId: 'test-client',
+    // Captures every payload before it reaches the network.
+    filter: (payload: TrackHandlerPayload) => {
+      sent.push(payload);
+      return false;
+    },
+  });
+}
+
+// tracker.ts runs on import, so each load needs its own module instance.
+async function loadTracker() {
+  trackerLoads += 1;
+  await import(`./tracker?load=${trackerLoads}`);
+}
+
+function trackedNames() {
+  return sent.flatMap((item) =>
+    item.type === 'track' ? [item.payload.name] : []
+  );
+}
+
+beforeEach(() => {
+  dom = new JSDOM('<!doctype html><html><body></body></html>', {
+    url: PAGE_URL,
+    runScripts: 'outside-only',
+  });
+  for (const name of DOM_GLOBALS) {
+    (globalThis as Record<string, unknown>)[name] = dom.window[name];
+  }
+  sent = [];
+  installSnippet();
+});
+
+afterEach(() => {
+  for (const name of DOM_GLOBALS) {
+    delete (globalThis as Record<string, unknown>)[name];
+  }
+  dom.window.close();
+});
+
+describe('window.op before the SDK loads', () => {
+  test('call queues the method it was given', () => {
+    const { op } = dom.window;
+
+    op.call(dom.window, 'track', 'user_login', { source: 'nextjs' });
+
+    expect(op.q?.at(-1)).toEqual(['track', 'user_login', { source: 'nextjs' }]);
+  });
+
+  test('events sent through call, apply and bind survive the SDK loading', async () => {
+    const { op } = dom.window;
+
+    op.call(dom.window, 'track', 'through_call');
+    op.apply(dom.window, ['track', 'through_apply']);
+    op.bind(dom.window)('track', 'through_bind');
+    op.track('through_method');
+    await loadTracker();
+
+    expect(trackedNames()).toEqual([
+      'through_call',
+      'through_apply',
+      'through_bind',
+      'through_method',
+    ]);
+  });
+});
+
+describe('window.op after the SDK loads', () => {
+  beforeEach(loadTracker);
+
+  test('call reaches the SDK method, the way Turbopack compiles window.op?.()', () => {
+    dom.window.op.call(dom.window, 'track', 'user_login');
+
+    expect(trackedNames()).toEqual(['user_login']);
+  });
+
+  test('apply and bind reach the SDK method', () => {
+    const { op } = dom.window;
+
+    op.apply(dom.window, ['track', 'through_apply']);
+    op.bind(dom.window)('track', 'through_bind');
+
+    expect(trackedNames()).toEqual(['through_apply', 'through_bind']);
+  });
+
+  test('the callable and method styles keep working', () => {
+    const { op } = dom.window;
+
+    op('track', 'callable');
+    op.track('method');
+
+    expect(trackedNames()).toEqual(['callable', 'method']);
+    expect(op.q).toBeUndefined();
+    expect(dom.window.openpanel?.options.clientId).toBe('test-client');
+  });
+});
diff --git a/packages/sdks/web/src/tracker.ts b/packages/sdks/web/src/tracker.ts
index 5e789082a..472f774dc 100644
--- a/packages/sdks/web/src/tracker.ts
+++ b/packages/sdks/web/src/tracker.ts
@@ -35,6 +35,11 @@ import { OpenPanel } from './index';
           if (typeof value === 'function') {
             return value.bind(op);
           }
+          // Turbopack compiles window.op?.(...) to window.op.call(...), and only
+          // the function target has call, apply and bind.
+          if (value === undefined) {
+            return Reflect.get(target, prop);
+          }
           // Otherwise return the property from op (for things like options, etc.)
           return value;
         },