Arizona State at No. 21 Colorado tops the Pac-12 this week

Here are some things to watch in Week 6 of the Pac-12 Conference football season:

GAME OF THE WEEK: Arizona State at No.21 Colorado. The Buffaloes (4-0, 1-0 Pac-12) are 4-0 for the first time since 1998, but have faced a relatively easy schedule so far. Colorado beat Colorado State, struggling Nebraska and New Hampshire in nonconference, then knocked off UCLA, which has yet to win under new coach Chip Kelly. A big test comes this week against the Sun Devils (3-2, 1-1). Arizona State won its first two games under new coach Herm Edwards, lost two tight road games then ran past Oregon State last week.

MATCHUP OF THE WEEK: Utah at No. 14 Stanford. The Utes (2-2, 0-2 Pac-12) may not have won a Pac-12 game so far, but they still have the conference's second-highest scoring offense and a physical, stingy defense. They will face another powerful team in the Cardinal, who are coming off their first loss of the season, 38-17 to Notre Dame. There will be plenty of hard hits in this game.

NUMBERS GAME: No. 18 Oregon and Southern California have a bye week. ... Oregon S Ugochukwu Amadi had two interceptions, including one for a touchdown, in last week's win over California, earning Pac-12 defensive player of the week honors. ... Washington QB Jake Browning became the school's all-time leading passer last week, reaching 10,347 career yards.

UPSET WATCH: California at Arizona. The Bears are 2 1/2-point road favorites over the Wildcats, but this will be a difficult test after losing to Oregon last week. Arizona rallied late in a four-point loss to USC last week.

IMPACT PERFORMER: Eno Benjamin, Arizona State. The sophomore running back had an OK start to the season, rushing for 283 yards and a touchdown the first three games. Benjamin had a breakout game last week against Oregon State, setting a school record with 316 yards rushing and four touchdowns to earn conference offensive player of the week honors.