Spain have a slender advantage at the top of the World Cup of Golf leaderboard after Rafa Cabrera Bello and Jon Rahm finished the first round three-under-par in Melbourne.
The pair carded 69 in their foursomes, scoring two birdies and an eagle, while a bogey on the fourth hole was their only blemish of the day.
France, China and the USA all sit one shot off the pace, while England's Chris Wood and Andy Sullivan remain in contention after carding a one-under-par 71 round.
Adam Scott, who picked up the trophy in 2013 alongside fellow Australian Jason Day, ended the day two-over-par with Marc Leishman following three bogeys and a solitary birdie.