Steve Clarke has described in-form Grant Hanley as Scotland's "rock" ahead of Tuesday's crucial World Cup qualifier in Austria.
After three years out of the international set-up, the Norwich centre-back has established himself as one of the first names on the team sheet since making a goal-scoring return to the side against Austria at Hampden in March.
Clarke believes Hanley, 29, will be a big player as Scotland aim to boost their hopes of making it to Qatar next year by coming away from Vienna with a positive result.
He said: "I think Grant has always been a good centre-back. Obviously when you are a young defender you can be a little bit more rash. He has grown into his game, he is a more mature player.
"I have always liked Grant as a player, even as a youngster you could see the qualities that he had. You knew he would develop and become better and better as he got more experience.
"In recent games for Scotland I think he has probably been our most consistent player. Not many people have mentioned it, but losing Grant in the game against Croatia (at Euro 2020) was a big factor in the game.
"We lost that big rock at the back, that steadying influence. He is a great lad, a great trainer, he doesn't cause one bit of trouble. He comes in and everybody respects him in the group just because of the way he conducts himself. He has been a big plus for us."
Clarke expects a tough test in Vienna and won't be reading anything into Austria's weekend collapse in Israel.
The Austrians have come under heavy criticism after suffering a surprise 5-2 defeat in Haifa on Saturday.
The result allowed Scotland to leapfrog Franco Foda's team into third place in Group F.
However, Clarke refuses to buy into the notion that an Austria team that took Euro 2020 winners Italy to extra-time before bowing out of the tournament a little over two months ago have suddenly become a nation in crisis.
He said: "They are a very good team. They showed that in the Euros. They came out of their group and took the Italians, the team that won it, all the way, which is a difficult thing to do. So they are a good team with good players.
"They have had one or two fitness issues and squad issues. They have players who they probably wanted to be in the squad who are not in the squad, the same as we have. It is one of those things you just have to deal with. We will go there and it will be a tough game. It will be a tough game for us and a tough game for them."
