Safari permanently disabled by macekrrz.com pop-up windows

Running OSX 10.9.5 on a late 2012 Mac Mini 2.6GHz Intel Core i7.

While completing research in Safari I got hijacked by a pop-up claiming my computer was infected and I should call a toll-free number to fix it (see attached image). It's a crafty pop-up though: it's a pop-up on top of a pop-up. The one on top is specifically designed in a window that doesn't fit the screen size, which is why you can't scroll down to the bottom to close it.

No other windows behind the pop-up are accessible, including the Safari "Preferences" and other menus...:(

Someone posted some possible solutions on an earlier thread. I've tried all these but none of them fixed the issue. I'm posting them here anyway so that the brainy dudes out there know these have already been tried.

1. Holding down "shift" while rebooting Safari doesn't work.
2. Pressing APPLE "W" (close Safari window) doesn't work.
3. Eventually, once you've used force quit several times on Safari, it'll actually ask you if you want to reopen it without opening any of the previous windows. Then, when you reopen Safari having asked NOT to reopen the windows from last time, it just opens them all anyway, along with the macekrzz.com pop-up.
4. Safari cannot be downloaded and reinstalled because it isn't available from the Apple website, so that doesn't work either.
5. Rewriting the page URL in the pop-up window to divert it to a safe website (having disabled WiFi) doesn't work either, because another pop-up window on top of the first one prevents you from accessing the URL bar.
6. I have also tried using APPLE + and APPLE - to increase/decrease the screen/window size. This is because the reason why you cannot close the pop-up on top of all other pop-ups is because it is specifically designed NOT to fit the screen size. It is impossible to scroll down to the bottom of the pop-up where the "close" button probably is, because it's somewhere off the bottom of the page.

Does anyone have any additional ideas, bearing in mind that none of the above solve the problem? I cannot use Safari AT ALL until I resolve this, and cannot re-install it either.