"This is our fifth successive win and the fifth successive clean sheet and this has been the key to our tremendous improvement," the Blues' assistant boss said after the 2-0 win at St Andrew's. "I thought the back four were exceptional. Not getting that second goal until the last minute made it difficult for us. "We have to be defensive in this league. We are all learning how to cope and in this division you cannot afford to lose goals. "We have enough up front to score goals and with the resilience at the back we are well on course. "The players deserve the credit for this improvement. In the past we have pushed up an extra player and left ourselves exposed. But now we concentrate upon our defence. It's a no risk approach. "As long as we keep a clean sheet I believe we have enough in the team to get that winning goal."