Jarrod Moseley challenged Poulter for a while, but he bogeyed the last to fall three behind the winner. Moseley finished with a 3-under 69 and tied Jonathan Lomas (68) and Darren Fichardt (68) for second place at 15-under-par 273.
Poulter stretched his overnight lead to three shots as he opened with a birdie at the par-5 second at the Wentwood Hills Course. After three consecutive pars, the Englishman missed the green at the sixth, but nearly chipped in for birdie. He settled for a tap-in par.
The 2002 Italian Open winner converted an up-and-down par at the ninth for his seventh of eight straight pars. After Moseley closed within one stroke with a birdie at the 11th, Poulter drained a lengthy eagle putt at the same hole to extend his lead to three. This was the only eagle of the week at the 621-yard par-5 11th.
Poulter then two-putted for par on the next three holes to maintain his lead. At No. 15, his second shot to the par-4 found a greenside bunker and plugged in the sand. He was unable to save par and his advantage slipped to two.
For the second straight day, Poulter bogeyed the par-4 16th. His second shot flew the green and he was unable to get up-and-down for par. He two-putted for par on 17 to keep a one-shot lead heading to the last.
Poulter closed out the victory in style as he birdied the par-5 18th for the fourth straight round.
Mark McNulty and Andrew Coltart shared fifth place at 13-under-par 275. Local favorite Phillip Price struggled to a final-round 74. He was joined in seventh place by Santiago Luna and Peter Fowler at 12-under-par 276.
Benn Barham carded a four-over 76 to finish in 79th place at the bottom of the leaderboard at 8-over-par 296, but he did record a hole-in-one at the par-3 ninth.