How to open PDF files automatically in Preview

Before upgrading to Safari 11, if I clicked on a link in Safari to a PDF, the file would automatically download to my downloads folder and Preview would open the file.

After upgrading, when I click on a link to a PDF file, a new tab opens in safari and the PDF is displayed in the safari browser. Preview no longer opens and the file does not download into my downloads folder.

How can I change it back to automatically opening in preview?

Thanks