Glasgow flanker Rob Harley has become the fourth emergency replacement to be called into the Scotland squad for their tournament in South Africa, after another injury-hit weekend left the team struggling for back rows.

Harley is heading out directly as a replacement for Ryan Wilson, who dislocated his shoulder against South Africa on Saturday and meant Scotland were left with only three fit loose forwards after tour captain Kelly Brown returned home after the first game.

Also leaving the tour is lock Jim Hamilton, although in his case it is a pre-arranged exit from the squad so that he can be with his wife, Rebecca, who is due to give birth to their second child on Thursday.

Harley had been unlucky not to make the tour in the first place, having played in three of Scotland's RBS 6 Nations matches in the spring, but he is delighted to have been called up and is hoping he will be able to feature against Italy on Saturday.

Harley, who made his first Test start in the 34-10 win over the Italians in February, said: "It's a bit of a shock but very exciting.

"I've never been out to South Africa before so it'll be good to go over there and hopefully I'll be able to make the squad for the game on Saturday. I know a little about Italy but I'm sure it'll be a different game over in South Africa with different conditions."

The 23-year-old is joining a squad that is feeling buoyed by their overall performance last weekend when they were leading South Africa, ranked second in the world, 17-6 after 58 minutes, and still within a score of snatching a win until the final move of the game, which sealed the 30-17 victory for the home side.

Centre Alex Dunbar, whose try immediately after half-time seemed to have set Scotland on their way, hopes his side can now use that display as a base for future performances.

"The game against South Africa is the starting point now for the standard of the defence and attack. We have to build on that," he said.

"We had a good performance against Italy in the Six Nations but everyone knows how hard it is going to be and we are looking to build on our last game. They have had a hard couple of games as well, so it will be a good game, I'm looking forward to it.

"The intensity we started with against South Africa with was much higher [than in the first match against Samoa]. We contested the breakdown a lot more and our line speed was a lot higher. They came in with the mentality that they wanted to dominate the gain line so we had to get off the line and meet them first."

It was that same added intensity that brought both pride and frustration to Scotland's defence coach Matt Taylor, who was encouraged by the level of desire but left wondering where it had all been during the opening match.

A few home truths to some of the under-performing players seems to have worked.

"We talked about our attitude and our work rate," he said. "Those two things really came out at the weekend but, for whatever reason, they were not where they needed to be against Samoa.

"The coaches talked a lot about that. I thought the attitude part of our game, in terms of line speed and collision, was top notch.

"Our work rate to make a tackle and get back up to reset the line were right up there - all those things that were in our control were up there. The challenge is that that has to be the standard. There is no point in going back to where we were against Samoa, we have to be consistent."