Clark was pleased with Birmingham's battling performance after twice coming from behind to earn a point.
He admitted: "Chris Burke changed the game for us after a disappointing first half only to concede another bad goal.
"We were then staring down the barrel but Kyle Bartley came up with the goods after going on as a late substitute.
"He has pestered me to allow him to go up front and he came up with the goods in terms of a great header from a set-piece.
"We are now unbeaten in five games. It is a good little run which shows we have solidarity.
"We would love to win but when you are going into injury time a goal behind you willingly take the point from the draw.
"Bartley is effective from set-pieces and we knew we had the height advantage when he went on late in the game.
"He is a very good athlete. He is quick and he can pass the ball. You see the size of him and when he attacks the ball it is very difficult for anyone to mark him.
"I was gutted when he had to come out of the team and now he is pushing to regain his place in the side.
Burke, however, was Birmingham's saviour as he won the penalty which his fellow Scot, Paul Caddis, scored in the 57th minute to cancel out a 22nd-minute strike by Mustapha Carayol.
Middlesbrough appeared to be heading for a long overdue win at St Andrew's when Daniel Ayala scored in the 80th minute.
But it was Burke who again engineered Birmingham's late equaliser with an accurate corner which Bartley headed home four minutes into injury time - just four minutes after coming on as a late substitute.
- Sports & Recreation
- Kyle Bartley