disappointed to lose by seven wickets in Abu Dhabi.
"The mood is good, we've moved on from the disappointing performance, obviously we were hurt quite a bit after the Test, we haven't played cricket like that in a long time and we were very, very disappointed," de Villiers said after team practice on Monday.
"We're finding ways to fix it and that's the most important thing. We've looked at a few areas where we went wrong and we're going to try and get it right," said de Villiers.
"It's a must-win game for us and we're going in there with that attitude to win that game, we're still the number one team in the world and we are going to play like it."
South Africa slumped to 249 and 232 against a spin-cum pace Pakistan attack and failed to stop their rivals from putting up a mammoth 442 for a comfortable win.
To add to South Africa's batting problems, first Test centurion Hashim Amla may not be available for the second Test as the reliable batsman returned home for the birth of his second child.
Left-hander Dean Elgar is likely to replace Amla.
Dale Steyn also suffered a back problem, but De Villiers believes the paceman will recover.
"He did tweak something in the fielding practice yesterday, but we think it's not too serious, so we are just taking a good precaution and making sure he will be ready for the second Test," he said.
De Villiers praised Pakistan's bowling, led by off-spinner Saeed Ajmal who finished with 4-74 in the second innings.
"I thought they bowled quite well with clever plans. But then again few soft dismissals including myself, you never know what could have happened," said De Villiers, referring to his bizarre run out in the first innings.
De Villiers played a defensive shot and was out of his crease after the slip fielder threw to wicket-keeper Adnan Akmal who ran the batsman out.
He hit a fighting 90 in the second knock.
"I think we didn't do the basics well, didn't adapt quickly to the conditions, few highlights were probably Hashim's innings and a couple of partnerships, and that was it, other than that it was quite a disappointing performance."
South Africa may also look at their spin option, replacing leg-spinner Imran Tahir for left-arm spinner Robin Peterson who finished wicket-less in the first Test.