Nick Watney shot a 66 to finish alone in third while Craig Lile, Lee Porter, Rob Bradley and Matthew Jones shared fourth place at 5-under-par 67.
McKenzie parred the first four holes at Redwood Meadows Golf & Country Club before picking up his first birdie of the day at the par-5 fifth. McKenzie then ran off back-to-back birdies starting at the par-5 eighth to reach 3 under around the turn.
The 37-year-old caught fire on the inward half with four consecutive birdies from the par-3 13th. McKenzie then parred his way in for his piece of the lead.
'If you hit into less trouble and make some putts, you tend to have low scores,' said the Australian. 'I didn't hit many fairways today but then again, if I only hit three fairways and shoot seven-under each time, there'll be a smile on my face.'
Compton had to deal with a weather delay in the afternoon but managed to grind out a strong showing thanks to a solid back nine.
The 24-year-old got off to a quick start before the rains came with birdies on three of his first four holes. He then added two straight birdies starting at the par-4 10th to continue his climb up the leaderboard.
After a bogey at the 14th, Compton, who completed his round as daylight was fading, closed with three birdies over his last four holes to join McKenzie in the lead.
'It was tough finishing in the dark, but maybe that was a good thing because I picked my line and trusted it,' said Compton. 'These greens have some undulation and you tend to over read them.'
Watney played the back side first and mixed seven birdies and a bogey to finish one shot off the pace.
Jason Buha, Matthew Goggin, Paul Gow, John Morse, Kevin Johnson and Todd Demsey are knotted at 4-under-par 68.