diff --git a/src/d3d9/d3d9_device.cpp b/src/d3d9/d3d9_device.cpp
index a98454c..7cbb03d 100644
--- a/src/d3d9/d3d9_device.cpp
+++ b/src/d3d9/d3d9_device.cpp
@@ -891,11 +891,60 @@ namespace dxup {
   HRESULT STDMETHODCALLTYPE Direct3DDevice9Ex::UpdateSurface(IDirect3DSurface9* pSourceSurface, CONST RECT* pSourceRect, IDirect3DSurface9* pDestinationSurface, CONST POINT* pDestPoint) {
     CriticalSection cs(this);
 
-    RECT destRect;
-    destRect.left = pDestPoint ? pDestPoint->x : 0;
-    destRect.top = pDestPoint ? pDestPoint->y : 0;
+    Direct3DSurface9* src = reinterpret_cast<Direct3DSurface9*>(pSourceSurface);
+    Direct3DSurface9* dst = reinterpret_cast<Direct3DSurface9*>(pDestinationSurface);
+
+    if (src == nullptr)
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: src was nullptr.");
+
+    if (dst == nullptr)
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: dst was nullptr.");
+
+    D3DSURFACE_DESC srcDesc;
+    D3DSURFACE_DESC dstDesc;
+    pSourceSurface->GetDesc(&srcDesc);
+    pDestinationSurface->GetDesc(&dstDesc);
+
+    D3D11_BOX srcBox;
+    srcBox.front = 0;
+    srcBox.back = 1;
+
+    UINT dstX = 0;
+    UINT dstY = 0;
+
+    if (pSourceRect != nullptr) {
+      srcBox.left = pSourceRect->left;
+      srcBox.top = pSourceRect->top;
+      srcBox.right = pSourceRect->right;
+      srcBox.bottom = pSourceRect->bottom;
+
+    }
+    else {
+      srcBox.left = 0;
+      srcBox.top = 0;
+      srcBox.right = srcDesc.Width;
+      srcBox.bottom = srcDesc.Height;
+    }
+
+    if (pDestPoint != nullptr) {
+      dstX = pDestPoint->x;
+      dstY = pDestPoint->y;
+    }
+
+    if (!src->isBoxValid(&srcBox))
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: box was invalid.");
+
+    if (srcDesc.MultiSampleType != D3DMULTISAMPLE_NONE)
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: src has multisampling.");
+
+    if (dstDesc.MultiSampleType != D3DMULTISAMPLE_NONE)
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: dst has multisampling.");
+
+    if (srcDesc.Format != dstDesc.Format)
+      return log::d3derr(D3DERR_INVALIDCALL, "UpdateSurface: src format is not the same as dst format.");
 
-    StretchRect(pSourceSurface, pSourceRect, pDestinationSurface, pDestPoint ? &destRect : nullptr, D3DTEXF_NONE);
+    // TODO: do we need to do staging here too? Look into this.
+    m_context->CopySubresourceRegion(dst->GetDXUPResource()->GetResource(), dst->GetSubresource(), dstX, dstY, 0, src->GetDXUPResource()->GetResource(), src->GetSubresource(), &srcBox);
     
     return D3D_OK;
   }
diff --git a/src/d3d9/d3d9_surface.cpp b/src/d3d9/d3d9_surface.cpp
index 1216191..40872e6 100644
--- a/src/d3d9/d3d9_surface.cpp
+++ b/src/d3d9/d3d9_surface.cpp
@@ -185,5 +185,36 @@ namespace dxup {
     if (config::getBool(config::GDICompatible))
       resource->GetResource()->QueryInterface(__uuidof(IDXGISurface1), (void**)&m_surface);
   }
+  bool Direct3DSurface9::isRectValid(const RECT* rect) {
+    if (rect == nullptr)
+      return true;
 
+    if (rect->right <= rect->left || rect->bottom <= rect->top)
+      return false;
+
+    if (rect->left < 0 || rect->top < 0)
+      return false;
+
+    D3DSURFACE_DESC desc;
+    this->GetDesc(&desc);
+    if (rect->right > (int)desc.Width || rect->bottom > desc.Height)
+      return false;
+
+    return true;
+  }
+
+  bool Direct3DSurface9::isBoxValid(const D3D11_BOX* box) {
+    if (box == nullptr)
+      return true;
+
+    if (box->front != 0 || box->back != 1)
+      return false;
+
+    RECT rect;
+    rect.left = box->left;
+    rect.top = box->top;
+    rect.right = box->right;
+    rect.bottom = box->bottom;
+    return this->isRectValid(&rect);
+  }
 }
\ No newline at end of file
diff --git a/src/d3d9/d3d9_surface.h b/src/d3d9/d3d9_surface.h
index d267589..9ace493 100644
--- a/src/d3d9/d3d9_surface.h
+++ b/src/d3d9/d3d9_surface.h
@@ -39,6 +39,9 @@ namespace dxup {
     void ClearResource();
     void SetResource(DXUPResource* resource);
 
+    bool isRectValid(const RECT* rect);
+    bool isBoxValid(const D3D11_BOX* box);
+
   private:
 
     IUnknown* m_container;