McKenzie and Bowden were part of a lucky contingent of players who finished their first rounds despite a four-hour weather delay.
Play was eventually suspended for the day when darkness settled in on Midland Country Club, and 72 players were forced to pick up their balls. The round will resume at 9:10 a.m. ET on Friday.
Jeremy Anderson is currently alone in third place at 5-under-par 67, while three players -- Danny Ellis, Notah Begay III and defending champion Charley Hoffman -- are one stroke further back in fourth place after opening-round 68s.
Jason Schultz is also at minus-4 through nine holes of his first round.
All in all there are 65 players within five strokes of the clubhouse leaders, including 33 who have yet to finish their first rounds. Of the players remaining on the course, 22 are minus-2 or better and only four of those have played at least nine holes.
But even with plenty of players lined up to challenge the clubhouse leaders, the start was still a good one for McKenzie and Bowden. Especially for McKenzie, who birdied his 72nd hole on Sunday to win the Gila River Golf Classic by one stroke over Jon Mills.