Major winners Rory McIlroy and Graeme McDowell are two shots off the early pace for Ireland on day one of the World Cup in China.
The 2009 runners-up trail Australia's Brendan Jones and Richard Green, who lead after an 11-under-par 61.
Scotland's Martin Laird and Stephen Gallacher are tied with Ireland after Thursday's opening fourballs.
England's Ian Poulter and Justin Rose are 10th after a 66, while Wales' Rhys Davies and Jamie Donaldson are 19th.
The two-time winners combined for a five-under 67 in the 28-team tournament.
Northern Irish duo McIlroy and McDowell, who were pipped by one shot by Italian brothers Francesco and Edoardo Molinari two years ago, eagled the par-five sixth and managed seven birdies in their opening round of the event at Mission Hills in China.
The pair are among the favourites to clinch the $2.4m (£1.5m) winning prize with both securing US Open triumphs since their last appearance.
McDowell admitted he was relieved when his partner parred the last after he had missed an eight-foot putt.
He said: "It would have been really disappointing not to have parred the last so it was good to see my partner knock that one in for a four.
"We gelled really well today and Rory's a pretty decent little partner."
McIlroy tweeted his content with a "solid" day on the course, believing their nine-under was a "good" score.
He added: "Hopefully more of the same tomorrow!"
The United States team of Matt Kuchar and Gary Woodland birdied five of their closing seven holes to finish the day tied with Netherlands in fourth at eight under par.
Ireland's last World Cup winners were Padraig Harrington and Paul McGinley in 1997.