diff --git a/core/server/services/api-version-compatibility/legacy-api-path-match.js b/core/server/services/api-version-compatibility/legacy-api-path-match.js
index 137912185a..70222a5c45 100644
--- a/core/server/services/api-version-compatibility/legacy-api-path-match.js
+++ b/core/server/services/api-version-compatibility/legacy-api-path-match.js
@@ -1,17 +1,19 @@
 const pathMatch = require('path-match')();
 
 module.exports = (url) => {
+    let basePath = 'ghost/api';
     let apiRouteMatcher = '/:version(v2|v3|v4|canary)?/:api(admin|content)/*';
+    let urlToMatch = url;
 
-    if (url.startsWith('/ghost/api')) {
-        apiRouteMatcher = `/ghost/api${apiRouteMatcher}`;
+    if (url.includes(basePath)) {
+        urlToMatch = url.split(basePath)[1];
     }
 
-    if (!url.endsWith('/')) {
-        url += '/';
+    if (!urlToMatch.endsWith('/')) {
+        urlToMatch += '/';
     }
 
-    let {version, api} = pathMatch(apiRouteMatcher)(url);
+    let {version, api} = pathMatch(apiRouteMatcher)(urlToMatch);
 
     if (version === [null]) {
         version = null;
diff --git a/test/unit/server/services/api-version-compatibility/legacy-api-path-match.test.js b/test/unit/server/services/api-version-compatibility/legacy-api-path-match.test.js
index b95271362b..bd00797f21 100644
--- a/test/unit/server/services/api-version-compatibility/legacy-api-path-match.test.js
+++ b/test/unit/server/services/api-version-compatibility/legacy-api-path-match.test.js
@@ -5,16 +5,22 @@ const legacyApiPathMatch = require('../../../../../core/server/services/api-vers
 describe('Legacy Path Match', function () {
     it('returns null, admin for all supported permutations', function () {
         const permutations = [
+            '/subdir/ghost/api/admin/',
             '/ghost/api/admin/',
             '/admin/',
+            '/subdir/ghost/api/admin',
             '/ghost/api/admin',
             '/admin',
+            '/subdir/ghost/api/admin/session/',
             '/ghost/api/admin/session/',
             '/admin/session/',
+            '/subdir/ghost/api/admin/session',
             '/ghost/api/admin/session',
             '/admin/session',
+            '/subdir/ghost/api/admin/session/something/',
             '/ghost/api/admin/session/something/',
             '/admin/session/something/',
+            '/subdir/ghost/api/admin/session/something',
             '/ghost/api/admin/session/something',
             '/admin/session/something'
         ];
@@ -26,16 +32,22 @@ describe('Legacy Path Match', function () {
 
     it('returns canary, admin for all supported permutations', function () {
         const permutations = [
+            '/subdir/ghost/api/canary/admin/',
             '/ghost/api/canary/admin/',
             '/canary/admin/',
+            '/subdir/ghost/api/canary/admin',
             '/ghost/api/canary/admin',
             '/canary/admin',
+            '/subdir/ghost/api/canary/admin/session/',
             '/ghost/api/canary/admin/session/',
             '/canary/admin/session/',
+            '/subdir/ghost/api/canary/admin/session',
             '/ghost/api/canary/admin/session',
             '/canary/admin/session',
+            '/subdir/ghost/api/canary/admin/session/something/',
             '/ghost/api/canary/admin/session/something/',
             '/canary/admin/session/something/',
+            '/subdir/ghost/api/canary/admin/session/something',
             '/ghost/api/canary/admin/session/something',
             '/canary/admin/session/something'
         ];
@@ -47,16 +59,22 @@ describe('Legacy Path Match', function () {
 
     it('returns v4, admin for all permutations', function () {
         const permutations = [
+            '/subdir/ghost/api/v4/admin/',
             '/ghost/api/v4/admin/',
             '/v4/admin/',
+            '/subdir/ghost/api/v4/admin',
             '/ghost/api/v4/admin',
             '/v4/admin',
+            '/subdir/ghost/api/v4/admin/session/',
             '/ghost/api/v4/admin/session/',
             '/v4/admin/session/',
+            '/subdir/ghost/api/v4/admin/session',
             '/ghost/api/v4/admin/session',
             '/v4/admin/session',
+            '/subdir/ghost/api/v4/admin/session/something/',
             '/ghost/api/v4/admin/session/something/',
             '/v4/admin/session/something/',
+            '/subdir/ghost/api/v4/admin/session/something',
             '/ghost/api/v4/admin/session/something',
             '/v4/admin/session/something'
         ];