Yates threw for 243 yards and two touchdowns in a 24-14 win over the Jacksonville Jaguars in both teams' preseason finale.
Yates had shown little in the team's first three exhibitions, completing 39.4 percent of his passes, with no touchdowns and two interceptions. Second-year player Sean Renfree posted better numbers and seemingly had an edge in the competition to be Matt Ryan's backup.
But Yates shined against the Jaguars.
His highlight throw was a 67-yard touchdown strike to Freddie Martino in the second quarter, a deep ball that put Atlanta up 21-7. His other TD came on a swing pass to Antone Smith, who broke several tackles during the 66-yard catch and run.
Yates completed 15 of 20 passes and was sacked twice.
With Henne resting, first-round draft pick Blake Bortles got the start for Jacksonville and extended his impressive preseason.
Bortles completed 4 of 6 passes for 86 yards, including a 57-yard TD strike to fellow rookie Marqise Lee on the first play of the second quarter.
"It was a good play," said Bortles, the third overall pick in May's draft. "I had him on a seam and threw a little later than I wanted to, but he did a good job staying alive and running down the field to make a play."
Bortles completed 32 of 51 passes for 521 yards in four exhibition games, with two touchdowns and no interceptions.
"I think it's going really well for us," Bortles said. "We've gone out wanting to do a couple of things this preseason, and we've accomplished a lot. We have a lot of work left to do, but I think everybody is happy with the preseason that we've had and is looking forward to getting ready for Week 1."
Despite Bortles' steady improvement, he's a lock to open the season on the bench behind Henne.
Henne ended the preseason 25-of-38 passing for 230 yards, with a touchdown and no interceptions.
More pressing questions for Jacksonville include the offensive line and the receiving corps.
Rookie center Luke Bowanko, a sixth-round pick from Virginia, started in place of Mike Brewster and looked sharp again. Brewster played in the second half and grounded a snap past quarterback Ricky Stanzi -- his third bad snap of the preseason.
Receivers Tandon Doss (ankle) and Ace Sanders (leave of absence) made their preseason debuts, but Doss sustained another ankle injury and could be out a while. Sanders is suspended the first four games of the season for violating the league's substance-abuse policy.