World No 1 Scheffler, who came into the year’s third Major with three wins in his last four starts, opened with a three-over-par 73 that was his worst first round score relative to par of his Majors career.

That left Scheffler in a share of 49th place, seven shots behind surprise leader Spaun and facing a stern challenge as he has never come back from outside the top 30 at the end of the first round to win an official PGA Tour event.

In the opening round, the brilliant Spaun fired a four-under 66 that was the day’s only bogey-free round, and the unheralded American will try to build on his hot start when he heads out from the first tee at 12.52pm.

South African Thriston Lawrence, who trails by one shot, will go out at 2.20pm from the 10th tee.

Five-time Major winner Brooks Koepka, one of 14 LIV Golf players in the field, also went out early and started his day two shots off the pace and in a three-way share of third place with South Koreans Kim Si-woo and Im Sung-jae.

Spaniard Jon Rahm, part of a group that finished the opening round three shots back of Spaun, also started early from the 10th tee.

Holder Bryson DeChambeau and Masters champion Rory McIlroy, who both struggled in the opening round, have afternoon tee times.