FOUR GAMES TO WATCH

No. 2 AUBURN (4-0, 2-0) at SOUTH CAROLINA (3-1, 1-1)

* Kickoff: Today, 4:30 PDT.

* TV: ESPN.

* Line: Auburn by 13 1/2 .

* Auburn update: The Tigers were sluggish in a 38-7 victory over Buffalo last week, leading only 10-0 at halftime. But they played without leading rusher Kenny Irons, who had a sprained toe and ankle. He returns against the Gamecocks. Irons, who has 322 yards in 66 carries, played two seasons at South Carolina before transferring in 2004. The Tigers have averaged 184 rushing yards, but Brandon Cox has passed for only 244 yards and no touchdowns the last two games.

* South Carolina update: Quarterback Syvelle Newton and receiver Sidney Rice etched their names in the school record book last week, connecting for five touchdown passes. South Carolina’s rush defense has holes, giving up 176.3 yards a game.

* Story line: Auburn can ill-afford to take another game too lightly if it has serious national-title aspirations. South Carolina has never beaten a No. 1- or No. 2-ranked team and has lost 19 straight against top-five teams.

* The pick: Auburn. A rested and rejuvenated Irons should run wild.

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PURDUE (4-0) at No. 12 NOTRE DAME (3-1)

* Kickoff: Saturday, 11:30 a.m. PDT.

* TV: Channel 4.

* Line: Notre Dame by 14.

* Purdue update: The Boilermakers rank in the top 10 nationally with averages of 40.8 points and 461.5 yards. Curtis Painter is fourth in the nation with 1,140 passing yards and Dustin Keller is 11th with 359 receiving yards, but the defense has yet to hold an opponent to fewer than 21 points. Purdue has a seven-game winning streak, its longest since it won 10 straight in 1998-99.

* Notre Dame update: This is the fourth consecutive Big Ten opponent for the Irish, who have had mixed results: an impressive victory over Penn State, an embarrassing home loss to Michigan and a stunning comeback victory over Michigan State. Brady Quinn, who has passed for 1,086 yards and 11 touchdowns, leads a unit that has twice scored 40 points but has rushed for only 299 yards.

* Story line: A Purdue victory would probably get the Boilermakers into the top 25 -- perhaps at the expense of Notre Dame.

* The pick: Notre Dame. It’ll be a high-scoring shootout and the Irish are better equipped for such a game.

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No. 24 GEORGIA TECH (3-1, 1-0) at No. 11 VIRGINIA TECH (4-0, 2-0)

* Kickoff: Saturday, 12:30 p.m. PDT.

* TV: ABC (Game Plan only on West Coast)

* Line: Virginia Tech by 9.

* Georgia Tech update: Since a 14-10 opening-week loss to then-No. 2 Notre Dame, Georgia Tech has outscored opponents, 97-33. Calvin Johnson has established himself among the top receivers in the nation with 19 receptions for 311 yards and five touchdowns. The Yellowjackets rank No. 18 in the nation in total defense, giving up an average of 249 yards.

* Virginia Tech update: The Hokies are second in the nation in scoring defense, giving up 5.8 points a game against opponents that are a combined 3-12. Defensive end Chris Ellis and receiver Josh Morgan are suspended for the game for violating team rules. Ellis has 12 tackles; Morgan has 10 catches for 161 yards and two touchdowns.

* Story line: The other teams in the Atlantic Coast Conference’s Coastal Division have losing records, so a conference title shot could be at stake. Georgia Tech lost, 51-7, to Virginia Tech last season.

* The pick: Georgia Tech. The Hokies have had a soft early-season schedule and won’t react well when pressed.

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No. 1 OHIO STATE (4-0, 1-0) at No. 13 IOWA (4-0, 1-0)

* Kickoff: Saturday, 5 p.m. PDT.

* TV: Channel 7.

* Line: Ohio State by 6 1/2 .

* Ohio State update: The Buckeyes have outscored opponents, 124-32. Troy Smith has passed for 884 yards and eight touchdowns. Ted Ginn Jr. and Anthony Gonzalez have combined for 35 receptions, 554 yards and seven touchdowns. The last time Ohio State visited Iowa was 2004 and the Buckeyes were defeated, 33-7 -- their most lopsided loss under Coach Jim Tressel.

* Iowa update: The Hawkeyes will be facing a ranked opponent for the first time this season. Drew Tate has passed for 687 yards and seven touchdowns. Albert Young, who finished fourth in the Big Ten with 1,334 rushing yards in 2005, has run for only 280 yards this season. The Hawkeyes have won 32 of their last 35 games at home.

* Story line: The national title is on the line every week for Ohio State, but a victory here and it can probably cruise to its Nov. 18 regular-season finale against Michigan.

* The pick: Ohio State. Iowa has looked a little shaky and that 2004 embarrassment is fresh enough so that the Buckeyes shouldn’t let down.