Jacquelin led Anthony Wall by a single shot with six holes left to play when play was halted.
After a 2 1/2-hour rain delay at Donnafugata Golf Resort & Spa in Italy, the tourney was suspended and set for a Monday finish.
Jacquelin came into the fourth round up by one shot and lengthened his lead to as many as three strokes before cooling off, allowing Wall to catch up.
Jacquelin had collected three birdies and a bogey in the final round before the rain delay.
Jose Manuel Lara was in third place at 9-under par with three holes remaining.