Blues recovered from a stuttering start to take the lead through Curtis Davies just before the break and the hosts went on to create several more good chances that they were unable to convert. Clark's men were subsequently punished as Kirk Broadfoot equalised on 73 minutes for the visitors and the match finished all-square at 1-1.
Clark said: "It was a nervy start from us but we grew into the game and finished the first-half really strong and could have been more than one up. We started the second-half really well too and unfortunately we couldn't get that decisive second goal. They scored a similar goal to us from a set-play, which was a bit frustrating, but I'm disappointed for the players because I think they deserved to win the game today.
"We have played with a lot of desire and tenacity - high-tempo, like I talked about before the game. And I think our four wide players have combined really, really well - Caddis and Burke on the right and Hancox and Ferguson on the left. We played a lot of our football on the front foot and Shane and Chris were getting the ball high up. We fizzed in some great crosses and on another day we could have had a couple more goals with a bit more luck.
"It was a blow really when young Mitchell had to come off with a tight hamstring and it's not looking too good for him for the weekend. It's a bit of a nightmare for us because you just get things going the way you want them to go and you get a setback."
Even after Broadfoot's leveller, Blues could have won it but Wade Elliott was guilty of the miss-of-the-season when he skied his shot when unmarked only a few yards out from goal. Clark though had some sympathy for the winger who has already contributed six goals to the cause this season.
"One of my coaches, Richard Beale, has seen a replay and he said that it looks like it's bobbled up a little bit," he explained. "We'd expect him to score but I'm not going to criticise anybody. I want him on Saturday to be in the same position to have the same chance because I know the next thousand times that he has that opportunity on the training pitch or in matches, he'll just tap in it. Unfortunately this time it didn't happen and it would have probably wrapped the game up for us."
Clark confirmed that Steven Caldwell was missing due to illness and his condition would be reassessed later in the week ahead of Derby County's visit to St. Andrew's. Paul Robinson came in to partner goal-scorer Davies at the heart of the defence and the boss felt that his team had a 'good balance' throughout the team.
He concluded: "I thought Paul did well and it was quite unique in today's world that we had five left-footers and five right-footers in the outfield ten. I thought we had a good balance and it looked that way at times. There are lots of positives and I'm absolutely gutted for the players because I think their performance and work ethic deserved more than what they got."