Matt Gogel fired a flawless eight-under 63 to set a Congressional Blue course record and grab the first round lead at the Booz Allen Classic in Potomac, Maryland, before lightning halted play.
Gogel sits three shots clear of fellow American Brett Wetterich, Swede Fredrik Jacobson and Britain's Lee Westwood.
Kevin Stadler was also on five-under through 14 holes when play was suddenly stopped late in the day because of dangerous conditions due to lightning.
Defending champion Adam Scott of Australia opened the defence of his title with a solid three-under 68 while most of the other top-ranked players struggled in the oppressive heat.
South African Retief Goosen, who will defend his U.S. Open title next week, had an uneven start, mixing five birdies with four bogeys to sit seven off the lead on one-under 70.
World number one Vijay Singh, who failed to make the cut last week at the Memorial, continued to search for his best form, settling for an even-par 71.
The hard-working had plenty of familiar company with world number four Phil Mickelson and number nine Padraig Harrington also sitting eight shots off the pace.
