USC vs. Washington State: How the Trojans and Cougars match up in critical Pac-12 game

No. 5 USC (4-0) vs. No. 16 Washington State (4-0)

Friday, 7:30 p.m., Martin Stadium, Pullman, Wash. TV: ESPN; Radio: 710

Marquee matchup

Quarterback Sam Darnold vs. Washington State’s secondary: Washington State has the nation’s 12th-best passing defense, averaging 142.3 yards a game with five interceptions and three touchdowns. Three of four starting quarterbacks haven’t lasted the full game against the Cougars, two because of injury and one because of performance. But none had close to Darnold’s talent.

Getting offensive

USC (492.0 ypg/37.0 ppg): USC is hurting at its skill positions. The Trojans will return starting running back Ronald Jones II from a thigh injury and No. 1 receiver Deontay Burnett is not expected to miss time with a shoulder injury, but Steven Mitchell Jr. is doubtful because of an injured groin. Last week against California, USC’s offense struggled on short yardage: USC converted three of eight opportunities on third and fourth downs of four yards or less. And long yardage too: Darnold completed just one pass longer than 15 yards.

Washington State (504.3 ypg/43.8 ppg): Luke Falk is probably the best quarterback Clancy Pendergast’s defense has seen in his current tenure. Falk has 12,266 yards and 103 touchdowns in his career. This season, he has 14 touchdowns to just one interception and has completed 77% of his passes. He is “about as efficient as there is in the league right now,” USC Coach Clay Helton said. The running game is an afterthought in the “Air Raid” system, averaging just 2.8 yards a carry.

Getting defensive

USC (370.3 ypg/24.8 ppg): USC forced six turnovers against Cal, including another forced fumble by Christian Rector, a backup who has quickly brought chaos to opposing backfields. He has 3.5 sacks and two forced fumbles in the last two games.

Washington State (262.3 ypg/18.5 ppg): Defensive lineman Hercules Mata’afa has eight tackles for loss, including 4.5 sacks, this season. “He’s a nightmare,” Helton said. Washington State lost linebacker Peyton Pelluer to a broken foot but is still on pace to be, by far, the best defense of coach Mike Leach’s six seasons in Pullman. The Cougars have scored three defensive touchdowns.

Something special

Erik Powell’s field-goal percentage, 69.2%, is third-best in Washington State history. For USC, Chase McGrath made all three field-goal attempts against Cal. Neither team has a return touchdown this season.

Of note

A victory would give USC its longest winning streak since a span from 2003 to 2005. … Washington State has not defeated a top-five Pac-12 team since a win over Washington in the 1992 Apple Cup.

Local ties

The Cougars have 40 Californians on the roster, including starting receivers Kyle Sweet (Rancho Santa Margarita) and Renard Bell (Los Angeles), running back Jamal Morrow (Menifee), safety Jalen Thompson (Downey) and punter Kyle Sweet (Rancho Santa Margarita).

USC has no players from Washington.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand