The 21-year-old rookie changed that in quick order thanks to a record-tying 61 that earned him a share of the lead.
Thomas played his final five holes in 5 under, capping his round with a 17-foot eagle putt on No. 9. At 12 under, he holds a share of the lead on the PGA Tour for the first time and will head into the weekend tied with Matt Kuchar and Webb Simpson.
Thomas opened with a 68 and began his second round with six straight pars, putting him closer to the cut line than the lead in Honolulu. From there he caught fire, making the turn with three straight birdies before closing with a birdie-par-birdie-birdie-eagle finish and an inward nine-hole score of 29.
It all added up to a 9-under 61, which tied the modern course record set by David Toms in 2006. Davis Love III shot a 60 at Waialae during the 1994 Sony Open, but that round came on a par-72 layout before the course was renovated.
Thomas won an NCAA title at Alabama in 2013 and had a successful rookie season on the Web.com Tour in 2014, leading the circuit in birdie average and winning an event during the Web.com Tour Finals. His best finish this season came at the Sanderson Farms Championship in November, where he tied for fourth.