Steyn grabbed a career-best 5 for 25 and Quinton de Kock smashed a maiden century as South Africa took an unassailable 3-1 lead in the series.
Abu Dhabi: Fast bowler Dale Steyn grabbed a career-best 5 for 25 and Quinton de Kock smashed a maiden century as South Africa took an unassailable 3-1 lead in the series against Pakistan with a 28-run victory in the fourth one-day international on Friday.
Steyn derailed the run-chase with three wickets in the 46th over that included captain Misbah-ul-Haq (65) and Umar Akmal (22) to bowl out Pakistan for 238 with four balls to spare.
Left-handed opening batsman de Kock (112) became the youngest South African batsman at the age of 20 years to hit an ODI century and anchored the Proteas to a series-best total of 266 for 5 after captain AB de Villiers won the toss and elected to bat.
South Africa now go into the last match on Monday at Sharjah with a record of winning all the seven bilateral ODI series against Pakistan, including a 3-2 win earlier this year at home.
"Nice to have Steyn in the team, I play around him and he has that killer instinct," de Villiers said. "If the decider had gone to Sharjah it would have been tight, but it's good we wrapped things up here."
Pakistan opening batsmen Ahmad Shehzad (43) and Mohammad Hafeez (33) gave a decent start of 74 before Pakistan lost three wickets in space of 11 runs.
Debutant Sohaib Maqsood resurrected the innings with 56 off 54 balls, hitting six fours and two sixes and added 88 runs with Misbah before Steyn broke through with two wickets in the batting powerplay.
De Villiers took a brilliant catch while running backwards at mid-off to dismiss Maqsood and Sohail Tanvir holed out at deep midwicket.
But Misbah and Akmal added 50 runs and brought down the target to 39 off the last five overs before Steyn returned and took the game away in one over.
Akmal was caught by Morne Morkel close to the third man boundary and Misbah couldn't clear de Villiers at midwicket before Saeed Ajmal was clean bowled as Steyn surpassed his previous best ODI figures of 5 for 50 against India at Nagpur in 2011.
"We were in a good position until the last five overs but that over (Steyn's) changed the game," Misbah said. "We missed couple of chances in the field as well and one of them cost over 100 runs."
And that chance came when Hafeez dropped a regulation slip catch of de Kock on 2, and the left-hander made Pakistan pay for it by scoring 112 off 135 balls with nine fours and a six.
Hashim Amla (46) and de Kock laid a solid foundation of 87 runs, and de Villiers (30) added another 69 with de Kock.
Ryan McLaren (28 not out) and JP Duminy (25 not out) provided an ideal finish by adding 52 quick runs off 38 balls.
Amla and de Kock should have both been dismissed in the fourth over, but first Hafeez missed a sitter off seamer Sohail Tanvir and then Misbah could not hit the stumps at the non-striker's end to run out Amla.
Both batsmen shared South Africa's best opening stand in 2013 on the same pitch where South Africa made 259 for 8 on Wednesday. Hafeez (2 for 34) finally knocked back Amla's offstump in the 19th over.
Faf du Plessis, who scored a half century on Wednesday, fell in Mohammad Irfan's second spell when he skied a catch to Saeed Ajmal, and de Villiers upped the scoring tempo by adding 35 runs in the batting powerplay.
Pakistan wasted another opportunity to dismiss de Kock on 95, but Ajmal could not gather Shahid Afridi's throw cleanly at the non-striker's end with the left-hander way out of his crease.
De Kock, who scored 40 on Wednesday when he replaced the injured Graeme Smith, raised his maiden century when he lofted Irfan for a big six over long on.
Junaid Khan (2 for 42), playing his first match of the series, finally had de Kock caught in the 43rd over when Misbah took a low catch at mid off. The late charge by McLaren and Duminy proved decisive in the end.