And each backup quarterback did it his own way.
Kizer and Boyle combined to complete 11-of-18 passes for 142 yards and three touchdowns with no turnovers to power Green Bay to a 28-26 win over the Houston Texans at Lambeau Field.
Both quarterbacks weathered slow starts but finished their series strong to lead three consecutive touchdown-producing drives between the second and third quarters.
"It's fun when we're out there and everything is clicking," Boyle said. "We both came off the field and said the ball was coming off our hands well today. It felt good to be out there."
Kizer, the incumbent No. 2 quarterback, was given the offense for the entire first half. While the Packers punted on their first three possessions, Kizer began to establish a rhythm midway through the second quarter when he connected with tight end Robert Tonyan in the seam for a 23-yard completion on third-and-7.
It would be the fourth and final series for Kizer, who finished with a 111.7 passer rating on 8-of-13 passing for 102 yards.
"To go out there and get that drive going before the end of the half was really nice," Kizer said. "We were able to spread the ball around, the run game was looking good, a couple big third downs and, obviously, Shepherd going out there and getting up on a ball that was a little high for him and coming down with it in the end zone. That's exactly how you want a drive to go."
Boyle entered the game under interesting circumstances in the third quarter after cornerback Chandon Sullivan returned a Joe Webb interception to the Houston 3-yard line, the fourth and final takeaway the defense and special teams generated for the Packers Thursday night.
Still, the offense needed seven plays to punch the ball in, but finally did so when Boyle hit receiver J'Mon Moore on a 1-yard touchdown.
On what was his only full series of the game, Boyle engineered a five-play, 77-yard scoring drive, which was buoyed by a 40-yard penalty for defensive pass interference committed against receiver Allen Lazard.
Three plays later, Boyle was alerted to a particular coverage the Texans had been showing in practice this week and made the proper check to Lazard, who came free past cornerback Lonnie Johnson for a 27-yard touchdown pass.
It wasn't until after the game Boyle even realized he'd thrown only five passes on the evening in what amounted to his first in-game action since last year's preseason finale in Kansas City.
"I think all three quarterbacks played really well today," said Boyle, also referring to undrafted rookie Manny Wilkins, who played in the fourth quarter. "When 40 percent of your passes are touchdowns, it's a good day. I only threw five passes technically but it was a good day to be out there and play-calling was great."
Kizer and Boyle have each played in a litany of different offenses over the past five years, but both feel comfortable with the scheme new Packers Head Coach Matt LaFleur employs.
The goal for both quarterbacks was to protect the football, which they did thanks in part to an offensive line that didn't allow a sack to the Texans.
After 11 practices – two of which came against the Texans - the Packers' backup quarterback competition appears to be officially off and running.
"After that game today, I think it really solidified the confidence this whole quarterback room has in the system," Kizer said. "Every guy who played in tonight's game looked really comfortable and was able to rip it. That's exactly what this system is set up for. I'm looking forward to getting another challenge next week and making sure we can cross our 'T's' and dot our 'I's' before we get into live bullets."
Running on 'E:' The coaches warned Ty Summers ahead of time that he might be gassed after Thursday night's preseason opener.
They weren't lying. Not only did Summers start alongside Oren Burks – the rookie inside linebacker played the entire game on both defense and special teams.
What really cemented Summers in the lineup was Burks leaving early in the first quarter with an injury, which led to Summers relaying the defensive play calls for the remainder of the game.
Summers finished with a game-high 10 tackles (nine solo). No other player on either side of the field had more than six.
"It was kind of expected," said Summers of his workload. "I was like, 'Hey, man, I need all the reps I can get.' If I'm gassed, if anything, I'm working on my cardio, so I loved it. You know, sore, that's all part of it, doing special teams and defense, but I appreciate they're willing to keep me in there."
Special moments: If the Packers were looking for a sign their special-teams woes from 2018 are behind them, Equanimeous St. Brown's fumble recovery for a touchdown may have been it.
The second-year receiver showed his 4.4 speed as a gunner on Green Bay's punt team when he pressured Texans returner Keke Coutee into a muffed punt midway through the first quarter.
St. Brown then had the presence of mind to jump on the ball in Houston's end zone, resulting in the Packers' first touchdown of the evening.
"I saw him misjudge it a little bit with the way he went forward and backwards," St. Brown said. "As soon as it hit him, I knew I had to get on it."
It was one of three takeaways the Packers forced in the opening quarter. Rookie cornerback Ka'dar Hollman jumped a route to intercept Houston quarterback Joe Webb on the Texans' opening possession.
Safety Raven Greene forced a Taiwan Jones fumble, which Will Redmond then recovered with seconds remaining in the first quarter to tilt momentum in the Packers' favor early.
"You want everybody to have energy on the sideline and be hyped," Hollman said. "I felt like stuff like that is going to be a game-changer."
Green Bay opened the preseason with a matchup against the Houston Texans at Lambeau Field.
Catching on: Three months ago, Shepherd was the only tryout player to receive a contract offer from the Packers following their rookie minicamp.
One catch after the next, however, the former North Dakota State slot receiver has continued to earn opportunities this summer, including his first NFL touchdown catch after staying on the same page with Kizer on a scramble drill.
"It's crazy being in the NFL and doing this," Shepherd said. "But I really believe in my ability, so I just go out here and show that I can play."