'They've won five Tests in a row and they've beaten the world champions'

Scotland scored 10 tries in beating Tonga 60-14 but coach Gregor Townsend is warning their defence must improve for much a sterner challenge against the in-form Wallabies next Sunday.

Scotland were devastating on the front foot but also let Tonga, who were missing key players and had little preparation, have some attacking passages of play and a consolation try midway through Saturday's second half.

Townsend is concerned defensive lapses could prove a lot more costly in their next clash at Murrayfield against the Wallabies.

"Defensively we'll have to be at our very best. Australia have shown they are a good attacking side and they are full of confidence," said Townsend.

"They've won five Test matches in a row and they've beaten the world champions (South Africa) twice.

"We set very high standards in our defence, and at times against Tonga it wasn't at those standards.

"I thought Tonga played really well. We didn't know what to expect from them, but I felt when they had the ball they caused us problems, so we'll have a few things to work on this week."

Scotland could only choose home-based players for the Test against Tonga but will, from this week, have a full squad as players are released by their English and French clubs, including the likes of British & Irish Lions Chris Harris, Stuart Hogg, Finn Russell and Duhan van der Merwe.

"We also have to see how quickly we can integrate the players who are going to come back into the team during the week.

"We've got an extra day to prepare which should help us but we know it's going to be a massive challenge on Sunday," Townsend added.