The starter didn't throw an incompletion, the backup led a trio of scoring drives and the youngster dazzled late in Denver.
Kirk Cousins, Trevor Siemian and Kyle Sloter combined to complete 24 of 32 passes (75 percent) for 276 yards and four touchdowns to lead the Vikings to a 42-28 win in the preseason opener against the Broncos.
"I thought offensively we played pretty well all night," said Vikings Head Coach Mike Zimmer.
Cousins, a prized signing in free agency, completed all four of his attempts for 42 yards. He connected with wide receiver Stefon Diggs for three completions for 35 yards, and found fullback C.J. Ham for a 7-yard gain.
"Did he have an incomplete pass? I don't think so," Zimmer pondered after the game. "I thought he did well. He was good in the huddle … I thought he played really well."
Cousins' strong start helped lead the Vikings on an eight-play, 75-yard touchdown drive that was capped off by a 1-yard touchdown pass to Diggs.
"We've been working for nine weeks in OTAs and then several weeks here in training camp, and even over the summer, thinking about football, and we finally got to go out in a game setting and produce and [it was] great to see 14 do what we know he can do," Cousins said. "We'll need to see a lot more of that all season long."
Siemian led three Minnesota scoring drives as he made his return to Denver after being with the Broncos for the previous three seasons. He was with the Broncos when they won Super Bowl 50, and later went 13-11 as Denver's starter over the past two seasons.
The quarterback, who was acquired via trade in March, completed 11 of 17 passes for 165 yards with two touchdowns and an interception in his Mile High homecoming.
"I think there are a couple plays I'd like to do over. But there are definitely some positives," Siemian said. "Some good and some bad, that's usually how it works out.
"I think we did some really good things. We ran the ball really well. We moved it at times really well," Siemian later added. "There were times it wasn't as clean as we wanted it to be, but I thought we had a clean procedure for the most part. This was just a first step for us, and there's definitely a long way to go. But I think we're pretty happy with where we're at right now."
Added Zimmer: "Overall, I thought he did pretty well."
Siemian said it was "good to see some old buddies" in his return to Colorado.
"A little weird for the first game back here, but once you start playing you kind of forget about those things," Siemian said. "But it's a little different for sure."
Siemian took over for Cousins on Minnesota's second drive, but the series ended when the quarterback was sacked near midfield. But the 26-year-old, who threw 16 touchdowns in his career in Denver, found running back Roc Thomas out of the backfield for a 13-yard score to end Minnesota's third possession.
On the next series, Siemian found wide receiver Stacy Coley for 19 yards and tight end David Morgan for 11 yards to move the sticks. Those plays eventually led to a 39-yard field goal by rookie Daniel Carlson.
Siemian then let Thomas do more of the work, tossing a screen pass to the running back. The undrafted rookie free agent scampered 78 yards untouched for the score.
"Those are always good if you can steal a few of those," Siemian said. "Those are fun for sure."
Sloter joined the Vikings after four impressive preseason games with Denver in 2017, completing 31 of 43 passes (72.1 percent) for 413 yards with three scores and no interceptions.
He put on a show again Saturday night when he led the Vikings on a seven-play, 75-yard scoring drive to clinch the victory with a 9-yard touchdown pass to wide receiver Chad Beebe.
Sloter audibled at the line of scrimmage to counter Denver's defense.
"I just knew they were bringing Cover 0, an all-out blitz," Sloter said. "I checked to a protection that would give me a little bit for time.
"Beebe wasn't quite out of his route yet, and I had some guys breathing down my neck, so I just put some air on it and [hoped] he could see the ball," Sloter added. "I just put it out there for him, and he made a play."
And if that wasn't enough, Sloter scampered in for a 14-yard rushing score later in the fourth quarter as the quarterback celebrated by sprinting down the Vikings sideline in jubilation.
Said Zimmer: "He did a nice job. He saw the blitz the one time … [had] the scramble at the end. He threw the ball good [and] took good care of the football."
Like Siemian, Sloter said he had some emotions in his return to Denver.
"I've got a ton of respect for that entire organization, the fan base … they've shown me nothing but love since the time I left," Sloter said of his return to Denver. "It's been fun to come back and see how they reacted and see that they still care.
"Colorado is kind of a second home to me because I did some growing up here, too," Sloter added. "Just excited to be back."
The trio helped the Vikings put up 406 yards of offense in the win.
Minnesota continues its preseason slate on Saturday at U.S. Bank Stadium with a noon (CT) matchup against Jacksonville.