In his first two rounds Wallace amassed 17 birdies to hold a commanding lead at a weather-affected tournament in Portimao, but his advantage was cut to just three shots by Sebastian Heisele on Saturday after a level-par 73 that included four bogies.
The Englishman did not give up any further ground on the final day, though, as he posted gains on seven, nine – for the fourth round in succession – 13 and 16 to finish on 21 under for the tournament.
After making inroads in round three, Heisele was unable to keep pace and slipped down to a share of fourth with Sam Walker on 15 under.
Julian Suri took advantage of the German’s worst round of the competition and looked as though the American could challenge for the win after recording nine birdies through 15 holes, but a dropped shot at the 17th ended his hopes.
Suri finished three shots adrift of Wallace, while Matthieu Pavon took third after a four-under 69.
Alvaro Quiros and Pontus Widegren dazzled by going eight under, though their efforts came too late to secure a place in the top 10.
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