Rory McIlroy and Shane Lowry both made strong starts to the AT&T Pebble Beach Pro-Am in America, with Paul Dunne and Graeme McDowell not far behind them.
McIlroy and Lowry both carded opening rounds of four under to leave them three shots behind joint leaders Kevin Streelman and Beau Hossler. They are tied 17th with a large group of players, including Spain’s John Rahm
McIlroy had shot five birdies and one bogey to leave him four-under after 15 holes of the Spyglass Hill course, before a wayward drive gave him another bogey on the 16th.
But the four-time major winner rallied to hole a birdie on the 18th and remain among the chasing pack.
Lowry didn't drop a shot at Monterey Peninsula, hitting birdies on 12 (his third) and 9 and an eagle on the par-four first.
Three shots back on one under are Dunne and McDowell, which was good enough for a piece of tied 69 on a crowded leaderboard. McDowell finished at 71 after double-bogeying the 17th hole.
Seamus Power finished the first day on one over with Padraig Harrington already adrift on four over.
The competition is being played over three courses in California – the 72-par Pebble Beach Golf Links, Monterey Peninsula Golf Club, which is a 71 par, and Spyglass Hill, another 72-shot track.
Streelman played Spyglass Hill on he first day while his fellow American, PGA Tour rookie Hossler, was on Pebble Beach. Lowry went around Monterey Peninsula while McIlroy played Spyglass Hill, meaning the Offaly man actually came in one shot less (67), even though they are tied on the same score.
Streelman shot seven birdies - including one on the final par-4 18th hole - at Spyglass Hill, while Hossler carded the same, with a spectacular 54-foot putt for birdie on the par-4 16th hole at Pebble Beach.
Dustin Johnson carded a five-under 67 opening round as he bids to hold on to his position as world number one but it was a disappointing day for defending champion Jordan Spieth, who had to settle for a round of 72 on the Monterey Peninsula course, making one birdie, one bogey and 16 pars.