Winner gets $2.07mn
feet from the hole and made the eagle putt to seize the outright lead.
Matsuyama then landed his tee shot inches from the cup and found a fairway bunker at the 18th, then sailed a seven-iron 30 yards over the green.
With an uncanny touch, he rolled a chip to two feet and tapped in to complete an epic round.
There was no secret Matsuyama found during the break. "I spent the hour just sitting in my car looking at my cell phone," he said.
Matsuyama's best prior 18-hole Masters score was a 66 in the final round in 2015. He
Augusta National announced prize money figures on Saturday with the same totals as the past two years, the winner taking home US$2.07mn from a total purse of US$11.5mn.
Three-time major winner Jordan Spieth, who snapped a four-year win drought last week in San Antonio, struggled to a 72 to stand six off the pace.
Justin Thomas, who would become world No 1 with a victory, was undone by a triple bogey at the par-five 13th and shot 75 to stand ten shots adrift.