In a see-saw second set, Williams raced into a 3-0 lead but then lost five games in a row to stand on the brink of defeat.

BBC: SPORT | Tennis | Williams stuns fifth seed Petrova

Centre Graeme Morrison was a stand-out in the two summer clashes with the Pumas but Glasgow's strongest area is the back row, where they can call upon John Barclay, Kelly Brown and Johnnie Beattie.

BBC: Scots can build on good work