Grand opening for Carroll, Seahawks

Fans are learning to expect the unexpected from Pete Carroll.

The Seahawks’ new head coach produced another surprise Sunday at Qwest Field.

Underdogs against NFC West favorite San Francisco, Carroll’s Seahawks instead looked like division powers in a 31-6 dismantling of the 49ers.

“There was just a lot of really good things that happened, and yet we have a million miles to go,” Carroll said. “This is our first game. Our first opportunity and we answered the opportunity. But now we have to go back to work and get stuff right.”

Seattle kept the mistakes to a minimum and used an aggressive, ball-hawking defense to take advantage of a young San Francisco team still finding its way.

The Seahawks kept Niners quarterback Alex Smith under steady pressure. The Seahawks had two sacks, hit the bewildered Smith several times and forced him to throw two interceptions, including one Marcus Trufant returned 32 yards for a touchdown.

Carroll, now 4-1 in NFL openers, became the second Seahawks coach to win his debut (Jim Mora is the other).

The Seahawks rolled despite the Niners having all the momentum early. Cornerback Nate Clements picked off a Matt Hasselbeck pass, setting up the first of Joe Nedney’s two 23-yard field goals that gave San Francisco a 6-0 lead.

But the 49ers squandered their early advantage, driving inside Seattle’s 10-yard line on their first three possessions but coming away with just the six points.

The Seahawks would make them pay. After the offense sputtered early, Hasselbeck led a seven-play, 64-yard drive, capping it himself with a 1-yard scramble.

It was just the beginning.

One play after Jordan Babineaux intercepted a Smith pass intended to Michael Crabtree, Hasselbeck found receiver Deon Butler on a double move in the back of the end zone for a 13-yard score.

The Seahawks led 14-6, and the rout was on.