World number 51 Todd shot a five-under-par round of 65 on day two of the tournament at TPC Southwind to leapfrog his compatriot Brooks Koepka, who started the day with a two-shot lead.

With storms forecast for the latter part of the day in Tennessee, organisers moved the tee times of the 78-strong field forward by four hours to ensure play was completed without any interruptions.

Todd's round featured no bogeys, with birdies coming at the second, seventh, 11th, 14th and 15th holes to leave him on 11 under par at the end of the day.

He has a two-shot lead ahead of countryman Rickie Fowler, who carded a three-under-par round of 67 to take outright second at nine under par.

Like Todd, Fowler also made five birdies in his round, with the only blemish on his card being a double bogey at the 11th hole.

There is then a three-way tie for third place at seven under par between South Korea's An Byeong-hun, who also shot a 65, overnight leader Koepka who shot a one-over-par 71 and another American, Chez Reavie.

One shot further back at six under par is South Korea's Kang Sung-hoon and England's Matt Fitzpatrick, who moves up 30 places on the leaderboard after carding a six-under-par round of 64, the joint-best round of the day.

All 78 players go forward to the final two rounds, with no cut in operation at this WGC tournament.

If a cut had been in operation, among the big names who would have missed it would have been Spain's Jon Rahm, the new world number one, who carded a four-over-par 74 and plummeted 26 places down the leaderboard into a tie for 62nd place.