Four of the top five teams in the AP poll will be in action this weekend, and all four are double-digit favorites. But AP top-five teams are just 2-12 ATS (against the spread) this season against unranked opponents, and 5-13 ATS as double-digit favorites -- including 1-10 ATS when laying at least 20 points.
Here are a handful of other general trends to watch out for in Week 8, before a closer look at the games involving ranked teams:
• Ranked teams are 19-41 ATS (.317) versus unranked opponents, on pace to be the worst mark since the AP poll expanded to 25 teams in 1989 (current worst: .420 in 1994).
• Underdogs in games between two FBS teams are winning SU (straight up) at a .300 clip (43-100), on pace to be the best mark in the past 40 seasons (current best: .288 in 1984). Underdogs getting 14 or more points are 34-18-1 ATS.
• Favorites in games between two ranked teams are 10-1 ATS.
• Road favorites are putting up 37.3 points per game, on pace to be the most in the FBS era (current high for a full season is 34.8 ppg in 2013). The over is 36-17-1 (6-6 last week) when the road team is favored. But road favorites are still just 22-32 ATS (7-5 last week).
Odds listed are from Caesars Sportsbook by William Hill and subject to change.
Illinois Fighting Illini at No. 14 Wisconsin Badgers (-20, 51.5), Friday, 8 p.m. ET
• Illinois is one of five teams 3-0 ATS or better versus ranked teams since last season. The others are Tulsa (5-0), East Carolina (3-0), Purdue (3-0) and SMU (3-0).
• The Fighting Illini are 7-2 ATS against Big Ten teams since the start of last season, including 5-1 ATS as a double-digit underdog.
• This would be the fifth straight meeting in which Wisconsin is favored by at least 20 points (2-2 ATS, 3-1 SU in previous four). In fact, it will be the first time Wisconsin has been favored by double digits in five straight games versus Illinois since the FBS/FCS split in 1978.