Els, the world's third-ranked player, shot a 68 for 19-under-par 269.
Els also won the Dubai tournament in 1994 and 2002.
Miguel Angel Jimenez and Stephen Dodd tied for second.
"For a long while, it seemed that it was not going to be my week and then the 18th changed everything," Els said. "I can't remember the last time I won a tournament with an eagle at the last. This is a big win for me."
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