Last season, the once-highly-touted quarterback prospect from Chicago beat the top-ranked Buckeyes nearly by himself. He threw for 140 yards and four touchdowns while also pitching in 70 rushing yards, including backbreaking runs on the final drive of the game as the Fighting Illini bled the last 8:09 off the clock.
This year he has taken a giant step forward as a passing quarterback while remaining a dangerous runner.
"I think he's throwing it extremely well," Ohio State head coach Jim Tressel said. "I think he's come a long way in his two and three quarters years or whatever it is and not lost that ability to run and so that will be a challenge for us. We haven't faced anyone like him, so it will be a good challenge."
Interceptions have been a problem, though. Williams has pitched a conference-high 14 picks in 10 games.
2. Can anybody help Williams?
In the aforementioned upset, Williams' 210 total yards were complemented by a combined 158 yards rushing from Rashard Mendenhall and Daniel Dufrene. This season, with Mendenhall having gone to the NFL, Williams is not only throwing for 276.9 yards per game, he also has more yards rushing (577) than any of his teammates.
Dufrene is back and averaging 63.9 yards per game (he missed one contest for personal reasons) while Jason Ford is the team's No. 3 rusher (239 yards in 10 games). Ford is a true freshman capable of a big game, as he showed with 172 yards against Indiana earlier this season.
"The depth chart that we received for them, they've got about five different running backs, so we don't know who is going to play, but they are all talented, from what I've seen on film," OSU cornerback Malcolm Jenkins said.
Then there is sophomore receiver Arrelious Benn, who leads the Big Ten in receiving yards per game (94.7) and is dangerous as a return man.
3. How will Ohio State try to defend the Fighting Illini?
The Buckeye defense is getting hotter as the temperatures descend in the Midwest.
In the past five games, Ohio State has allowed five touchdowns while facing three of the top five scoring offenses in the Big Ten.
Next up is No. 2 Illinois, which averages 31.4 points per contest. The Fighting Illini lead the Big Ten and are 15th nationally in yards per game (447.6) and this year prefer to do their damage through the air (277.9 yards) as opposed to the past couple of seasons when they were a run-oriented squad.
Ohio State's recent run of success in stopping foes has coincided with a willingness to attack teams in a variety of ways, including some weeks heavy with man coverage in the secondary and others that lean more heavily on zones.
Last year the Buckeyes never seemed to get their bearings as the Illini totaled 400 yards, including a Tressel-era-high 260 on the ground, so it will be interesting to see how OSU attacks this season.
"I think if we can hold onto the ball, eliminate big plays and tackle in space we can do a good job," Jenkins said.
4. Can Terrelle Pryor continue to progress?
Thanks in large part to improved footwork in the pocket, Ohio State's freshman quarterback took a big step forward in his development last week against Northwestern.
Now the challenge is to keep progressing and to do so against a talented defense that will use a pass defense scheme Tressel said the Buckeyes only see once per year, when they face Illinois.
OSU receivers coach Darrell Hazell said the goal of the Illini scheme is to prevent teams from completing passes over the middle, but that might not affect Pryor to a great degree as some of his best success has come on deep routes on the outside.
5. Can the Buckeyes keep improving up front?
Illinois has managed to play the Buckeyes tougher than most of the rest of the Big Ten the past two seasons by being physical with Tressel's team and winning battles up front on both sides of the ball.
Ohio State's defensive line in particular struggled last season, troubles that seemed to carry over into the first part of this season. However, the Buckeye tackles and ends have raised their play of late, a trend they will hope to continue to slow down Williams and friends.
The OSU offensive line has had a harder go of it, but Tressel said they showed some signs of getting better last week. "I thought that we did some things better, not enough things better and we need to take another step this weekend and it will be a more difficult step."