One of the tour's longest hitters (he ranks fourth, averaging more than 309 yards per drive), Johnson saw that his accuracy problems (he ranks 195th in that category) mattered less at Atunyote, with its wide fairways and length past 7,500 yards.
Steadily, Johnson moved closer to the lead in the third round. His 70 left him two shots back of Tag Ridings and Charles Howell III when play got underway on Sunday, as Johnson went out paired with Allenby, a half hour ahead of the leaders.
Allenby made the big early move. The Australian, winless on the PGA Tour since 2001, birdied the 2nd, 3rd and 5th holes to zoom to nine under par and go in front, while Howell and Ridings struggled. Ridings, in fact, would shoot a 79 to fall far back.
Starting on the 6th hole, Allenby ran off nine consecutive pars, and that figured to be enough, since all sorts of players would rise to seven or eight under, then drift back with bogeys.
Meanwhile, Johnson moved to eight under with birdies on holes 6 and 8, only to bogey the 9th to drift back to seven under. He had a birdie-bogey shift on 12 and 13, and was two shots back of Allenby when the pair reached the par-4 15th hole.
Here, it began to turn. Allenby, accurate all day, suddenly saw his drive hook right into the trees. Despite some nice recovery shots, Allenby bogeyed, and Johnson was one back of him and Overton, who birdied the 14th to move to eight under.
Trying to regain his early magic, Overton instead bogeyed 16 and 17, falling into a large tie for 10th that included Nick O'Hern, Pat Perez, Joe Ogilvie and Charles Warren.
So it was now down to Allenby and Johnson. And on the long par-4 17th, Johnson crushed a drive, leaving him a wedge to the green that he stuck close. The birdie putt tied Johnson with Allenby as they went to the 624-yard par-5 18th hole.