diff --git a/src/d3d8/d3d8_device.cpp b/src/d3d8/d3d8_device.cpp
index f0315d8c0..3ae328bdb 100644
--- a/src/d3d8/d3d8_device.cpp
+++ b/src/d3d8/d3d8_device.cpp
@@ -309,6 +309,11 @@ namespace dxvk {
           D3DFORMAT           Format,
           D3DPOOL             Pool,
           IDirect3DTexture8** ppTexture) {
+    // D3D8 returns D3DERR_INVALIDCALL for D3DFMT_UNKNOWN
+    // before clearing the content of ppTexture.
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     InitReturnPtr(ppTexture);
 
     if (unlikely(ppTexture == nullptr))
@@ -344,6 +349,11 @@ namespace dxvk {
           D3DFORMAT                 Format,
           D3DPOOL                   Pool,
           IDirect3DVolumeTexture8** ppVolumeTexture) {
+    // D3D8 returns D3DERR_INVALIDCALL for D3DFMT_UNKNOWN
+    // before clearing the content of ppVolumeTexture.
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     InitReturnPtr(ppVolumeTexture);
 
     if (unlikely(ppVolumeTexture == nullptr))
@@ -371,6 +381,11 @@ namespace dxvk {
           D3DFORMAT               Format,
           D3DPOOL                 Pool,
           IDirect3DCubeTexture8** ppCubeTexture) {
+    // D3D8 returns D3DERR_INVALIDCALL for D3DFMT_UNKNOWN
+    // before clearing the content of ppCubeTexture.
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     InitReturnPtr(ppCubeTexture);
 
     if (unlikely(ppCubeTexture == nullptr))
@@ -444,6 +459,11 @@ namespace dxvk {
           D3DMULTISAMPLE_TYPE MultiSample,
           BOOL                Lockable,
           IDirect3DSurface8** ppSurface) {
+    // D3D8 returns D3DERR_INVALIDCALL for D3DFMT_UNKNOWN
+    // before clearing the content of ppSurface.
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     InitReturnPtr(ppSurface);
 
     if (unlikely(ppSurface == nullptr))
@@ -472,6 +492,11 @@ namespace dxvk {
           D3DFORMAT           Format,
           D3DMULTISAMPLE_TYPE MultiSample,
           IDirect3DSurface8** ppSurface) {
+    // D3D8 returns D3DERR_INVALIDCALL for D3DFMT_UNKNOWN
+    // before clearing the content of ppSurface.
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     InitReturnPtr(ppSurface);
 
     if (unlikely(ppSurface == nullptr))
@@ -499,8 +524,13 @@ namespace dxvk {
           UINT                Height,
           D3DFORMAT           Format,
           IDirect3DSurface8** ppSurface) {
+    // Only D3D8 CreateImageSurface clears the content of ppSurface
+    // before checking if Format is equal to D3DFMT_UNKNOWN.
     InitReturnPtr(ppSurface);
 
+    if (unlikely(Format == D3DFMT_UNKNOWN))
+      return D3DERR_INVALIDCALL;
+
     if (unlikely(ppSurface == nullptr))
       return D3DERR_INVALIDCALL;