Open a URL in browser & redirecting current page to another page

We have a login page, while loging into the application, we need to check a pop-up window condition,

If condition is true,
then we need to show a third party URL in a new browser tab and redirect the current page (Login.aspx) to Home.aspx page.

Here, we need to perform two operations one after the other. That is, show pop-up and redirect to new page.

If condition is false,
then we NO need to show the pop-up window, just redirect to the Home.aspx page.

Here, only redirection no pop-up window.

So, when it is false it is working fine.
But, when it is true, it is redirecting to the Home.aspx page with out showing pop-up window in a seperate browser window.

Need any suggestions on this .