Five things to watch: Ravens-49ers

This Thanksgiving night contest features two division leaders: the San Francisco 49ers, who are on the verge of clinching the NFC West, and the Baltimore Ravens, who are tied with the Pittsburgh Steelers atop the AFC North. San Francisco has won eight straight games and hasn't lost since Sept. 18. The Ravens have won seven straight at M&T Bank Stadium, which is currently the second-longest home win steak in the NFL.

Here are five things to watch:

1. Ravens need to get off to a fast start. The 49ers are 4-0 in the Eastern time zone this season, but they are traveling cross country on four-days rest. San Francisco coach Jim Harbaugh said earlier this week that his team got "the short end of the straw" as far as scheduling, so it's in the head of the 49ers. San Francisco could get off to a sluggish start as a result. The Ravens have jumped on teams at the start of games, outscoring opponents, 62-30, in the first quarter. The Ravens are 28-5 under John Harbaugh when scoring first.

2. X-factor is Frank Gore. The Ravens' run defense ranks fifth in the NFL, but it's been Baltimore's undoing this season. In their past two losses, the Ravens have given up 100 yards to Jacksonville's Maurice Jones-Drew and Seattle's Marshawn Lynch. Baltimore's focus will be stopping Gore, who has the most 100-yard games (29) over the past six years. To stop Gore, you need to be as physical as he is. Ravens inside linebacker Ray Lewis, who missed his first game last Sunday since 2007, has been limited in practice this week.

3. The decision-making of Alex Smith. One of the reasons for the 49ers' surprising success has been the play at quarterback. Smith just doesn't lose games. He has thrown four interceptions, which is the fewest among NFL quarterbacks with multiple starts. The Ravens thrive on creating turnovers and picked off Bengals rookie Andy Dalton three times Sunday. Since 2008, only the Green Bay Packers have more interceptions than the Ravens.

4. Which Joe Flacco will show up? The national television audience has seen the best and the worst of the Ravens quarterback. On Sunday Night Football against the New York Jets, Flacco didn't complete a pass in the second or third quarters. On "Monday Night Football" in Jacksonville, he went the first 40 minutes without recording a first down. And on Sunday night in Pittsburgh, he led the Ravens on a 92-yard winning drive in the final minutes of the game. It'll be interesting to see what kind of performance the Ravens will get out of Flacco against the NFL's 23rd-ranked pass defense.

5. Field-goal battle could heat up. The defenses for Baltimore and San Francisco have allowed the fewest offensive touchdowns this season. The Ravens have given up a league-low 13 offensive touchdowns, while the 49ers are right behind with 14 given up. This could mean a lot of field goals and possibly a lot of long-range field goals. San Francisco's David Akers has made all five of his kicks beyond 50 yards. Baltimore's Billy Cundiff has missed five of his six attempts from that range.