Jordan Spieth birdied the final hole to give him and teammate Ryan Palmer a share of the lead at the new-look Zurich Classic of New Orleans.
The pair posted a bogey-free 66 in the alternate shot format at TPC Louisiana to match the early target set by Kyle Stanley and Ryan Ruffels.
Charley Hoffman and Nick Watney eagled the 18th to move into a four-way tie for third on five under, with Patrick Reed and Patrick Cantlay a further shot back.
Palmer and Spieth made a steady start with a two-putt birdie at the second and a six-foot gain at the seventh, before holing a putt from a similar distance at the par-five 11th.
Spieth chipped in from the 14th fairway for a birdie and Palmer saved par from 12 feet at the next, with the pair picking up another shot at the 16th and rolling in a 15-footer at the last.
Earlier in the day, Stanley and Ruffels birdied their opening four holes and briefly went two clear of the chasing back with four gains in a six-hole stretch after the turn.
Stanley then missed the green with his tee shot into the par-five ninth - their final hole - to post a closing bogey.
Reed and Cantlay had threatened the outright lead with five birdies in seven holes on their second nine, only to bogey their final hole after failing to get up-and-down from the bunker.
Ian Poulter, who lost his full PGA Tour playing rights last week, and Geoff Ogilvy sit in the group on three under that also includes Brooks Koepka and younger brother Chase.
Top seed Jason Day and playing partner Rickie Fowler opened with a one-under 71, while Henrik Stenson and Justin Rose lie six strokes off the pace.
Watch the Zurich Classic of New Orleans throughout the week live on Sky Sports 4 - your home of golf. Live coverage begins on Friday at 8.30pm