Pakistan captain Misbah-ul Haq called on his top order to play their part to prevent South Africa clinching the one-day series after the fourth match on Friday.
Pakistan trail 2-1 after South Africa secured a commanding 68-run win in the third match in Abu Dhabi on Wednesday.
Chasing a challenging 260-run target, Pakistan were dismissed for 191 with leg-spinner Imran Tahir taking 4-53.
Pakistan's top order flopped again and only a 61-run partnership for the eighth wicket between Wahab Riaz (33) and Sohail Tanvir (31) gave the total some respectability.
The batsmen failed to chase 184 during their one-run defeat in the first match in Sharjah and struggled to put 209 on the board in their 66-run victory in the second fixture in Dubai.
"It's the same old story. I think we need to think about our batting if we want to save the series," said Misbah after Wednesday's match.
"Our batsmen get starts but are not able to convert them into big scores, and we all have to think that 20s and 30s are not going to win matches for us."
Pakistan have played six one-day series against South Africa but never won one.
Misbah said he could not explain the consistent batting failures.
"I think we got a good start and then there was no excuse, we should have won the match," he said of the 50-run start by Ahmed Shehzad (32) and Mohammad Hafeez (15).
Pakistan then lost five wickets in the space of 31 runs, slumping to 116-7 from 86-2.
"I don't have an answer and as professionals when we get set we must take it further," said Misbah.
He praised Tahir, who conceded 18 runs in his first two overs but went on to dismiss Misbah, Umar Akmal (seven) and Asad Shafiq (11).
"When wickets were falling it was good for him and he kept attacking and he gives them an attacking option," said Misbah of Tahir, who was born and brought up in Pakistan before emigrating to South Africa.
South Africa's captain was also full of praise for the leg-spinner.
"Imran is a world-class bowler," said AB De Villiers.
"For me, the main thing is that he brings a lot of intensity to the whole unit and obviously he also has a hell of a lot of skill in all the formats that he plays in."
Tahir took eight wickets in the second Test to help South Africa level the preceding two-match series 1-1.
"He brought that intensity into the team tonight and the whole team was lifted, and it's great to have him back in the green and gold again," said De Villiers.
He praised the team effort, especially the half-centuries from Faf du Plessis and Jean-Paul Duminy.
"I thought we did the basics well, still we could have got to 280, but still all in all the batsmen did well, and that's what we were talking about leading up to the match and a few guys put up their hands including Faf," he said.
"I am very happy for him under pressure and that tells a lot about his character and also JP."
Friday's game is in Abu Dhabi and the fifth and final match takes place in Sharjah on Monday, before two Twenty20s in Dubai on November 13 and 15.