The Australian-born second row also played five games for the 2009 Lions but just missed out on a Test spot.
And Townsend, who was the starting fly-half when the Lions secured a stunning series success against the Springboks in 1997, believes his countryman should be given great credit for his own achievements with Britain and Ireland's elite as well as with Scotland.
"I first met Nathan when he joined our tour to New Zealand as a replacement in 2000," said Townsend, who is currently Scotland's attack coach.
"What an effort he made to come back from serious injury early in his career and he went on to become one of the best ever players to pull on the Scotland jersey.
"I thought he was really unlucky on the 2009 Lions tour to South Africa.
"He played so well yet did not get into the Test team and, remember, he played in the back-row on that tour and looked the part, which shows what a player he is."
Those sentiments were echoed by Scotland boss Robinson who believes the former Edinburgh, Perpingan, Leinster and now Clermont Auvergne stalwart has proved himself to the ultimate professional.
"He is one of Scotland's toughest ever competitors and a fantastic role model for all young Scottish players," said Robinson.
"For him to play the way he has for Scotland on so many occasions has been fantastic.
"He had a couple of serious injuries, he's been able to play all round the world and perform very, very well and that's what you want from a player; the player that will turn up and always give everything.
"He was always calm before a game but when he went on the pitch he absolutely delivered a phenomenal performance every single time. To have the ability to do that is a great skill."