At the other end, Johnson had an effort deflected wide before Hemed cleared Jason Shackell's header off the line.
Soon after the opening goal, Brighton were dealt a blow when March was stretchered off after failing to shake off an earlier injury, but within a minute, they almost found a second goal as Murphy fired straight at Lee Grant.
Derby had been on the back foot but they finally produced a positive response through Johnson, who had a long-range drive well saved by David Stockdale, but it did not take long for the former Norwich City man to find the net.
After Jacob Butterfield's corner was swung into the box, Johnson was on hand to power a header past Stockdale to help the Rams into the break on level terms. body check tags ::