Struggling Blues twice came from behind to take the three points, following on from their midweek draw at Blackpool, and Clark stressed the need to build on that momentum.
He said: "It's important now that we kick on. This has happened on a few occasions this season and the next game it's gone flat.
"We've now taken four points from two tough games. We've got Wolves next Saturday - a big Midlands derby - and we need to continue getting positive results.
"Hopefully it'll give the lads belief. We've just beaten an excellent team who are going to be right in the mix and we can go on from there."
Marlon King scored twice, taking his tally to nine in as many games, but Clark refused to single out individuals for praise.
He said: "I think the whole team deserves credit because of the character and desire we've shown to bounce back and to get the result against a good side.
"We fell behind and deservedly so. We didn't get near Middlesbrough in the early part of the game. They've got talented players and when you give talented players time on the ball they've got three or four options.
"But when we had the ball we created some good opportunities and we just didn't get the rub of the green with some officiating again, unfortunately, which seems to be happening to us on a regular basis.
"But when you take into consideration the quality of the opposition and how they played, the resilience and character of my team, you've got to be delighted with the result."