Shane Lowry and Padraig Harrington carded an opening round 63 in the two-man team event at the Zurich Classic to sit four shots off leaders Chez Reavie and Lucas Glover, and Xinjun Zhang and Zecheng Dou.
The Irish pair are joined by American Chad Campbell and Australian Matt Jones on nine-under par in New Orleans the fourballs format.
Tommy Fleetwood and Chris Paisley combined for an opening round of 62 to sit just two shots off the lead.
Fleetwood is the reigning Race to Dubai champion while Paisley claimed his first European Tour title earlier this year but both men are still waiting for their first professional wins in America.
Fleetwood birdied the fifth and ninth, Paisley made a gain on the sixth and both men birdied the second and seventh as they turned in 31.
It continued to be a real team effort on the back nine, with a Fleetwood birdie on the 12th sandwiched by Paisley gains on the tenth and 16th before Fleetwood completed a birdie-birdie finish.
The Ryder Cup pairing of Justin Rose and Henrik Stenson were at seven under alongside Graeme McDowell and Ian Poulter, and defending champions Jonas Blixt and Cameron Smith.
