Two Palmer interceptions, two late fumbles and a safety were more than enough to turn a back-and-forth contest into a comfortable victory for San Francisco. When the Cardinals have been at their best offensively this season — i.e. vs. the Colts, Falcons and Rams — they’ve protected the football. Todd Bowles’ unit might have bailed out Arizona’s offense against the Seahawks, but banking on a repeat performance this week would be an unwise decision.University of Phoenix Stadium will be packed Sunday, but it would all be for naught if the home crowd is silenced early on with a handful of costly mistakes. Keys for the 49ers1. Get after Palmer Palmer has never been known as an athletic quarterback, and his immobility is only highlighted by the fact that he’s dealing with a sprained ankle. Couple that with his tendency to turn the ball over when under pressure, and it makes sense that San Francisco would do everything it can to pressure the former No. 1 overall pick out of USC. But Arizona has gotten creative in its protection, using tight ends and backs to help an offensive line that can get outmatched on the edges. Still, San Francisco shouldn’t have much of an issue dialing up the pressure on Palmer, and that will likely mean trouble for the Cardinals. 2. Find Vernon DavisIt’s no secret that despite the success of the Arizona Cardinals’ defense this season, it’s struggled against tight ends this season. The 49ers have one of the league’s elite receiving tight ends in Davis, and he went off to the tune of eight catches for 180 yards and two touchdowns in the teams’ first matchup this season. San Francisco’s offense has struggled to find a rhythm throughout parts of the season, but Davis gives them an outlet when things aren’t going well. If the 6-foot-3, 250-pounder can continue being a safety net for Kaepernick, it’s only going to mean good things for the 49ers. 3. Start fastSunday’s game is obviously a high-stakes contest for both teams involved, and the Cardinals will come out as fired up as they’ve been all season. Couple that with a noisy University of Phoenix Stadium, and the ingredients are there for the Cardinals to build early momentum and roll from there. The 49ers need to create something positive early to take the crowd out of the game and deflate a pumped up Arizona team. It doesn’t matter much whether that comes in the form of an early turnover or big play on offense, as long as San Francisco can manufacture some kind of momentum for itself. The 5: Takeaways from the Coyotes’ introduction of Alex Meruelo Derrick Hall satisfied with D-backs’ buying and selling In the teams’ first head-to-head showdown back on Oct. 13, the Cardinals hung tough at Candlestick Park for about three-and-a-half quarters before the wheels fell off. Costly fumbles by Alfonso Smith and Larry Fitzgerald and an 18-play, 89-yard touchdown drive sealed Arizona’s fate in a 32-20 loss.Keys for the Cardinals1. Don’t focus on the scoreboardIn an effort to add more meaning to their Week 17 slate of games, the NFL moved the Buccaneers-Saints game back to the same time slot as the Cardinals-49ers.While they need Tampa Bay to win in order to have a shot at postseason play, the Cardinals can’t make scoreboard watching their focus on Sunday.If they do, a very talented 49ers team will have no problem taking advantage.“The only thing that’s going to matter to us is what’s happening on the field,” Cardinals coach Bruce Arians said Friday. “That game doesn’t matter unless our scoreboard is reading right.” Let’s hope that decree on Friday holds true if the games remain tight late Sunday afternoon.A win in Seattle and a Tampa Bay win in New Orleans will mean absolutely nothing without an Arizona win, as well.