"A lot of these guys play at the same level all year and know each other well, so we are an unknown quantity really and there might be some complacency towards us. We'd like to surprise them and show them we can play."
The format is two rounds each of foursomes and fourballs. A 4-under 68 helped Graeme McDowell and Rory McIlroy catch Australians Richard Green and Brendan Jones as the two nations claimed the halfway lead.
The Australians were two clear overnight after a blistering 61 in the Four-balls, but had to scrap hard for a 70 in the more demanding foursomes format. Having birdied the second and bogeyed the fourth, the duo from Down Under had a slice of good fortune when Green chipped in from a bunker at the fifth, turning a likely bogey into a birdie in the process.
At the sixth, however, Jones sent a brilliant second shot to 15 feet and left-hander Green sunk the eagle putt.
The three-time European Tour winner holed from a similar distance at the 13th but two bogeys over the closing stretch left the event wide open.
It was Ireland's past and present US Open champions who took advantage, the pair responding to three-putt bogeys on the 11th and 13th with six birdies, the last of which came at the driveable 16th when McDowell splashed out of a bunker to two feet.
"I think both of us are very pleased about the score that we ended up shooting," said McIlroy, ranked second in the Official World Golf Ranking. "I think anything in the 60s in the foursomes format is a very reasonable score out there.
"There is still a lot of golf to be played this week, so it will be nice to get out there tomorrow again and enjoy the fourballs, and be aggressive and make a few more birdies.
"I think we are very pleased with how today went and we're looking forward to the weekend."
Only six shots separate the top 20 teams, with Scotland's Stephen Gallacher and Martin Laird in third on 12-under.
