The Spaniard began the final day five shots behind the in-form Sebastian Soderberg, who had led from the outset of the tournament, which was reduced to 54 holes after Saturday’s third round was cancelled due to thunder and lightning in the Shenzhen area.
Soderberg started the day with a three-shot lead but he was reeled in by Otaegui following his flawless display of seven birdies to set the clubhouse target at 18-under-par.
The Swede was on the same score heading down the last but hooked his tee-shot into the penalty area and despite reaching the par-4 in three, he could not hole the monster par putt which would have extended the tournament.
Soderberg went on to three-putt for a double bogey and a level-par 72, leaving him tied for third alongside England’s Paul Waring and Switzerland’s Joel Girrbach, with Migliozzi in second place at 17-under thanks to a lengthy birdie on the final hole for a 67.
Victory gives Otaegui the fifth DP World Tour title of his career and earns him a place at this month’s PGA Championship at Valhalla Golf Club after he finished in the top three of the tour’s Asian Swing rankings with Soderberg and Keita Nakajima.