Pakistan went down by an innings and 92 runs in the second Test in Dubai yesterday as the two-match series finished level at 1-1.
It deprived Pakistan of adding to their only other series win over South Africa in 2003 and it once again highlighted their inconsistency after they had won the first Test in Abu Dhabi by seven wickets.
That had followed an embarrassing Test defeat to minnows Zimbabwe last month.
"We must accept that after one or two good performances we get relaxed."
Pakistan's top order once again faltered as they were bowled out for a paltry 99 in the first innings in Dubai, with opener Khurram Manzoor bagging a pair, a week after hitting 146 in Abu Dhabi.
"We need to work hard on mental strength, every innings is a new innings, if you have scored a 200 then the team expects the same from you in the other innings, you can't live on one hundred," said Misbah.