question about Response.Write/Redirect

Question

how can i use these two commands together when i try it it works but the redirect activates before i can see my write. for example when i click my update button inside the code i would put all the stuff i want to send to a database, but if an error occurs i want to reply with a message then redirect after the user clicks ok on that pop-up. anyways heres the code im using for the .write .redirect:

Response.Write("<script>alert('Update Unsuccessful');</script>");
Response.Redirect("Page.aspx");

ill have this in an if statement checking for problems if something comes up i want the user to know what they did wrong then it redirects them to the same page.