Dubai:A classic one-day series will have a deciding encounter after Pakistan produced another nerve-jangling run chase in Dubai to clinch a second one-wicket victory in the space of two matches with one ball to spare.
Zulqarnain Haider struck the winning run after just about managing to keep his head as everyone else lost theirs, and South Africa will be left to wonder how they let another match slip away.
When Morne Morkel removed Abdul Razzaq in the 47th over, having also bagged Younis Khan for a measured 73, the game, and the series, was in South Africa's grasp with Pakistan needing 31 off 23 balls, but again their bowling and fielding couldn't cope under pressure.
Graeme Smith, back leading the side after missing two matches with a hand injury, spilled a tough chance from Wahab Riaz and then Dale Steyn, who was playing his first international of the season, conceded 12 off the 48th over as two short balls were pulled past short fine-leg.
South Africa messed up a chance to run out Wahab when Johan Botha produced a wild throw from the outfield as he came back for a third, then in the penultimate over another chance was missed when Morkel hurled the ball past the stumps from his follow through and two overthrows ensued. Amid all the drama, it left Pakistan needing four off the last over but a final twist seemed almost inevitable, and duly arrived when Wahab was finally run out.
It meant Haider was on strike with three needed from three balls and he levelled the scores with a chip over midwicket as Parnell missed the chance to win the game for South Africa by failing to flick the ball into the stumps.
The next delivery was short on leg and, after the manic scenes, it was a relatively calm nudge to square leg which sealed the result.
It was breathless cricket, the third game in a row that had shown how much the 50-over game still has to offer.
There was proper, conventional batsmanship from Younis and Smith, innovative striking from Botha, quality fast bowling from Morkel and Shoaib Akhtar and impressive spin played out in front of a crowd that grew after the sun had gone down.
Chasing 275 was always going to be tough but this was a better surface than for the third game, which had been too slow to enable clean strokeplay.
Younis, who only hit one boundary, was carrying his team into a winning position alongside Razzaq as the pair added 49 for the sixth wicket with the batting Powerplay still up their sleeve.
It was the ideal combination to complete the chase - Younis' calmness alongside the brute force of Razzaq - but Morkel removed Younis via an inside edge and two balls later Abdur Rehman was run out in a hopeless mix-up.
Pakistan had been ahead, or within touching distance, of the asking rate throughout the chase but South Africa had kept chipping away.
What made the final disintegration of their fielding so surprising was that it was shaping as the difference between the teams. Younis and Asad Shafiq added 56 for the third wicket before Shafiq was run out by a direct hit from mid-on by Wayne Parnell, then Shahid Afridi - who took three boundaries in an over off Steyn to kick-start the innings - was brilliantly caught at long-off by Parnell as he tried to launch Botha into the stands.
Imran Farhat had fallen in the first over, trapped lbw from around the wicket by Morkel, but Mohammad Hafeez set a positive tone and latched onto the extra pace of Steyn, who returned after a lengthy absence.
It was fascinating viewing as Steyn worked through the gears and Hafeez was winning the early battles with a string of boundaries.
Steyn had his revenge when Hafeez tried to whip a straight delivery through the leg side and was comfortably leg before.
Ultimately, though, his 10 overs cost 79 runs, the second most expensive analysis of his career, and questions will again be asked about how South Africa bowled in the closing overs, especially as Rusty Theron, who kept his nerve in the previous match, was left out.
Smith had a far more productive return to action although his lay-off had only been two games after taking a blow on his hand in the opening encounter in Abu Dhabi.
He was soon back in the grove and eased to a 57-ball half-century, adding 94 for the third wicket with de Villiers, who laboured against Pakistan's spinners in a boundary-less 70-ball innings.
Smith missed out on a hundred when he tried to work Hafeez through the leg side, and for a while South Africa lost momentum as Wahab put himself on a hat trick by yorking JP Duminy and David Miller.
Botha responded with a string of clever boundaries, including two reverse sweeps off Hafeez and a brace of scoops over short fine-leg against Wahab. The impetus was back in South Africa's camp, but it's been impossible to predict the outcome in this series and this was to be another thriller to the end.