Blues lost the 19-year-old with a broken fibula and tibia after he and Luciano Becchio collided innocently soon after the Argentinian's equaliser.
"Will's young team-mates and friends are distraught, they were in tears out there," Clark said.
"I said, `Let's try and win the game for Will'. We couldn't quite do it but I thought we deserved to do so.
"We will give him as much care and support as possible and have him back fit and strong for next season.
"We should be celebrating a fantastic performance by my young players, but this is a real downer. I heard the snap and was hoping it was a shin pad. It was an innocuous one with two players going for the ball."
Birmingham's squad contained nine teenagers, four of them in the starting line-up. Yet it was 34-year-old Wade Elliott who turned David Norris near the half-way line and steamed unchallenged through the middle to fire into the top-right corner from 25 yards.
Norris atoned for his part in the opening goal by winning the ball off Curtis Davies and threading it through for Becchio to find the bottom corner for his 19th goal of the season.
- Sports & Recreation
- Luciano Becchio