"I felt comfortable, like I never left," Jackson said after he helped lead the Vikings to a 20-16 victory Sunday over the Detroit Lions. "Like I was still out there the whole time. Just took over.

"Coach Bev (Darrell Bevell, offensive coordinator) called a great game when I was in. We had great continuity with what I wanted to do. It helped a lot."

Jackson, who replaced injured Gus Frerotte in the second quarter, knew he could be in this position.

He had watched Frerotte absorb big hits in recent weeks and barely get up. So Jackson wasn't shocked when Frerotte couldn't return against Detroit because of a lower-back injury he suffered in the first half.

Jackson knew during practice that it was likely he could be called to play.

"You try to prepare week in and week out the same, but it's just more urgency on my part, on everybody's part, knowing that anybody's number can be called," Jackson said. "That's from me to (No. 3 QB John David) Booty to the backup right tackle. You've got to be ready at any time."

Jackson certainly was ready Sunday, leading the Vikings to two second-half touchdowns and a field goal.

Jackson completed 8 of 10 passes for 105 yards with a touchdown. He didn't throw an interception. He didn't play scared. He didn't mess up.

"He came out, he was very prepared, he wasn't nervous," left tackle Bryant McKinnie said. "He got right back in the swing of things and helped us get a victory."

Jackson's 11-yard touchdown pass to tight end Visanthe Shiancoe capped an 11-play, 90-yard drive that stretched into the fourth quarter.

Shiancoe fell to the ground on the play, but it was all a fake, designed to throw off the defense. He immediately jumped back up and ran into the end zone, where Jackson found him for the touchdown.

Jackson said Shiancoe "did a good job of selling it. It was a naked (bootleg), and I just tried to give a good fake because everybody is looking at Adrian (Peterson) all the time. (Shiancoe) did a good job and got open."

The drive also included a 16-yard pass from Jackson to Bernard Berrian on second and 11 at the Minnesota 22. Later, on third and 3 at the Detroit 43, Jackson connected with Sidney Rice for 15 yards near the right sideline.

Those accurate passes were missing too often when Jackson was the starter in the first two games of the season. The Vikings started 0-2, and coach Brad Childress inserted Frerotte into the lineup for the rest of the year, barring an injury.

Frerotte suffered a lower-back injury and did not return after throwing an interception with about three minutes left in the second quarter.

"Can't say enough about Tarvaris coming in the game and how he played with limited reps," Childress said. "That's what happens at that position. But I thought he did a great job coming in, moving the Football around, converting third downs, directing the show. He knew exactly what he was doing."

Jackson said: "No matter how you're able to get in, no matter what the situation is, you just want to be ready and have fun while you're out there."

Jackson also made a key play with about four minutes left in the fourth quarter, Bobby Wade for 13 yards on third and 4 at the Minnesota 45.

"It was big," Jackson said. "It kept the ball in our hands, kept the defense off the field, kept the clock running. It was real big. He did a great job of getting open. I just tried to get him the Football in a position where he could make the catch, and he did a great job."

Jackson said it was gratifying to help the team again, finally.

"I just had to be ready because you never know, and it really showed today," Jackson said. "Coach (Childress) has been saying it. He guaranteed me I'd probably be in there because of how the NFL is. That's the thing. I'm just happy we got the win."