Chris Paterson gave Scotland an early lead but the Springboks hit back with three tries in quick succession in the middle of the first half to effectively end the match as a contest.
Bryan Habana, Jaque Fourie and Fourie du Preez were the men on the scoresheet as Jake White's side underlined their World Cup credentials at Murrayfield.
Despite the 27-3 defeat at the hands of England's pool rivals, Blair is adamant the game was the perfect way for Scotland to complete their preparations for the tournament in France.
Indeed the Edinburgh star, now established as Scotland's first-choice scrum-half, believes it is as physical a game as he has played in.Â
It was certainly a step-up from the match against Ireland a fortnight previous, when Frank Hadden's men ran in four tries against the Triple Crown champions.
Blair said: "It was tough. We played in a similar kind of way compared to two weeks ago but the physical nature of the South Africans was different.
"I think they had seen how we played against Ireland came out to make a point that they are the most physical team in world rugby.
"I think we still showed some very promising signs, although there were times when things didn't go quite so well.
"The seven-minute period when they scored their tries was a bad period but we regrouped and had a lot more possession in the second half although we couldn't quite make it pay.
"I was pretty pleased with how it went for me. It was a tough, tiring game and certainly that first 20 minutes was 'welcome back to Test rugby'!
"Speaking to a few guys in the changing room they were blowing a bit too and I think the South Africans were the same. It was just a lightning quick start to the game."
Blair feels the work-out against White's side puts them in great shape for the trials which lie ahead, especially if they can pick up a few tricks of the trade from the streetwise Springboks.
The 26-year-old said: "This gets us battle hardened. That is as physical a game as we've played in and I include New Zealand in that - so it was an invaluable work-out.
"With Portugal in two weeks' time we want to get on a roll. I'm sure some of the other guys will get some game time but it's important to put in good, convincing performances ahead of the New Zealand and Italy games.
"I think we showed we can mix it with them (South Africa) but there are also things we can still learn from them.
"When we were defending our first hit was excellent - they were going back after the first hit. But then their guys were clinging on and making a mini ruck to get some go-forward. We were maybe a little bit slower in doing that and getting a secondary shunt.
"Then when we were taking the ball in we'd make the yards but as we were hitting the ground they came in and put the hit in. That's something we can learn from and identify the time when there is an opportunity for a turnover."