While the Seahawks’ 23-0 win over the Giants might have lacked a little something in artfulness and drama, it more than made up for it in importance. With the win, Seattle improved to 12-2 and clinched at least a tie for the NFC West title. And while the Seahawks were unable to clinch the title outright when the 49ers won at Tampa Bay, all Seattle has to do now is win one of its final two home games — against Arizona next Sunday and St. Louis on Dec. 29 — to clinch both the division and the No. 1 seed in the NFC. It’s only the third time in franchise history the Seahawks have won 12 of their first 14 games, the others coming in 1984 and 2005. The Seahawks also got their first shutout of the season with a defensive performance that might have been even more dominating than the stats illustrate. Seattle picked off New York quarterback Eli Manning five times — increasing his NFL-leading total to 25 — and didn’t allow the Giants past their own 47 until under eight minutes were left in the game. Seattle preserved the shutout when Richard Sherman tipped a Manning pass in the end zone to teammate Earl Thomas with 4:17 left. Sherman and Byron Maxwell also had two interceptions each as Seattle had five interceptions in a game for the fifth time in team history and first since 2007 (the team record is seven against San Diego in 1998). It took Seattle a while to get going as the Seahawks punted on four of their first five possessions. The Seahawks had a 3-0 lead at the end of the first quarter thanks to a 19-yard punt return by Golden Tate to the Giants’ 42 that resulted in a 49-yard field goal by Steven Hauschka. Manning’s second interception of the game turned the tide Seattle’s way. Midway through the second quarter, Manning lofted a pass to Hakeem Nicks down the sidelines with Sherman in man coverage. Sherman got the inside position and outleaped Nicks to pick it off at the Seattle 38.