Seattle Seahawks (13-3) at San Francisco 49ers (12-4). From Levi's Stadium. A scintillating race for the NFC's No. 1 playoff seed comes down to this Week 18 showdown in Santa Clara, site of Super Bowl LX in five weeks. Mike Macdonald's Seahawks lost 17-13 to San Francisco in Week 1, one of just two games in which they were outgained. QB Brock Purdy and the Niners, like Seattle, are on a 6-0 run. RBs Zach Charbonnet and Christian McCaffrey are both coming off season-high rushing games.