Tommy Fleetwood and Chris Paisley fired a combined 10-under 62 to get within two strokes of the early leaders at the Zurich Classic of New Orleans.
The English pair birdied 10 holes in the fourball format to sit tied-third, as morning pacesetters Chez Reavie and Lucas Glover share top spot with Chinese pair Xinjun Zhang and Zecheng Dou.
None of the 80 teams are over par after the opening day at TPC Louisiana, where players will play foursomes during the second round before playing another round of each format over the weekend.
"It's obviously a big tournament, but it's kind of just good fun having a good friend alongside you and a really good player as well," Fleetwood said.
Fleetwood holed a 15-footer at the second and posted a 20-foot gain at the fifth, as Paisley made back-to-back gains over his next two holes on the way to the pair reaching the turn in 31.
The duo carded matching gains at the 10th and Fleetwood posted a close-range birdieat the 12th, before the European No 1 finished their round by picking up shots on each of his final three holes.
Reavie and Glover followed a first-nine 29 with five birdies in a six-hole stretch to set the clubhouse target, only for Zhang and Dou to match it late in the day by birdieing their final three holes.
Shane Lowry and Padraig Harrington posted a blemish-free 63 to sit three strokes back in a share of ninth place, with Scottish pair Russell Knox and Martin Laird a further shot back.
Ryder Cup teammates Henrik Stenson and Justin Rose posted a seven-under 65, which was matched by Ian Poulter and Graeme McDowell and defending champions Cameron Smith and Jonas Blixt.
Watch the Zurich Classic of New Orleans throughout the week live on Sky Sports. Live coverage continues with Featured Groups on Friday from 2.15pm.