South Africa sealed an emphatic series win after beating Ireland by 174 runs in the second one-day international in Abu Dhabi.The Proteas, who won the first of three ODIs by 139 runs on Wednesday, took an unassailable 2-0 series lead after racking up 343 for five before bowling Ireland out for 169 in the 31st over of their reply.Tristan Stubbs starred for South Africa with the bat, thumping 112 off 81 balls, while pace bowler Lizaad Williams took three Ireland wickets for 36 runs.Stubbs struck eight fours and three sixes in his maiden ODI century and put on 133 for the third wicket in partnership with Kyle Verreynne, who made 67 off 64 deliveries.Ireland lost openers Andrew Balbirnie and captain Paul Stirling cheaply to slump to seven for two and were reduced to 65 for six by the 13th over.Tail-enders Graham Hume (21) and Craig Young (29 not out) put on 52 for the last wicket but their defiant stand merely delayed the inevitable.The two sides will meet again in the final ODI on Monday at the same Sheikh Zayed Stadium venue.South Africa 343-4 (50 overs)Ireland 169 (30.3 overs)