Updated

The Oregon Ducks will attempt to defend their No. 2 ranking on Saturday night, as they begin Pac-12 Conference action against the California Golden Bears at Autzen Stadium.

Cal has been bogged down by one of the nation's most difficult early slate of games, having already lost to a pair of nationally-ranked Big Ten teams in Northwestern (44-30) and Ohio State (52-34). Even in the Bears' lone win over Portland State they did not look very sharp, letting the FCS squad hang around before squeaking out a 37-30 win.

"We have started poorly for three weeks," Cal head coach Sonny Dykes said. "I don't really have an answer at this point, but it is something we need to get fixed."

The loss of Chip Kelly in the offseason has not hindered the Oregon football program one bit here in the early part of the 2013 campaign. Under new head coach Mark Helfrich, the Ducks have shined with three straight blowout victories over Nicholls State (66-3), Virginia (59-10) and Tennessee (59-14), and after starting the season ranked No. 3, they have crept up to No. 2.

While Helfrich is surely enjoying the ride so far, he is fully aware that it won't be smooth sailing the whole season, and he needs to prepare his team for a strong Pac-12 run.

"At some point somebody is going to score on us and we have to see how we're going to respond and I think our guys did a great job of just playing the next play," Helfrich said.

Cal leads the all-time series with Oregon, 39-34-2, but that has skewed heavily in the opposite direction in recent years with the Ducks winning four in a row. The Bears are just 2-11 in Eugene since 1980.

The Golden Bears' early-season troubles cannot be attributed to their offense, which has performed well in scoring 33.7 ppg and racking up 556.0 ypg, ninth most in the nation.

The pass-happy squad is led by freshman Jared Goff, who ranks fourth in the FBS in passing yards with 1,306, while completing 61.3 percent of his tosses with seven touchdowns and four interceptions.

Chris Harper (21 receptions, 324 yards, three TDs) and Bryce Treggs (28 receptions, 317 yards, TD) are an outstanding duo out wide, with the two ranking sixth and seventh, respectively in the Pac-12 in receiving yards. In all, Goff has hooked up with 14 different receivers this season.

The rushing attack averages just over 117 yards per game, with Brendan Bigelow (175 yards) earning the most work.

Unfortunately for Cal, its defense has not shown the ability to stop anyone, as the unit ranks 119th in the country in allowing 42.0 ppg.

The defense's saving grace is that it has forced six turnovers through three games. Khairi Fortt leads the way with 25 tackles and 2.5 TFL, with Hardy Nickerson (24 tackles) and Jalen Jefferson (24 tackles, 2.5 TFL, sack) hot on his heels.

Under the new regime, Oregon's offense has not skipped a beat, as it ranks second in the nation in both scoring (61.3 ppg) and yardage (672.0 ypg), trailing only Baylor in both categories.

Marcus Mariota is proving why he's a bona fide Heisman contender. Not only is he completing nearly 60 percent of his passes for 889 yards, seven touchdowns and zero interceptions, but he has rushed for 262 yards and four more scores. In a nearly flawless performance against Tennessee the last time out, the sophomore had 456 passing yards, 27 rushing yards and five total touchdowns.

"His performance is one for the ages, especially with him being young and finally getting his first 400-yard game," wide receiver Josh Huff said of his signal caller. "He's probably one of the best quarterbacks in the nation."

Huff cashed in six receptions for 125 yards and a score versus the Vols to add to his team lead in catches (14) and yards (298). Bralon Addison (174 yards, two TDs), Johnny Mundt (121 yards, two TDs) and Daryle Hawkins (103 yards, TD) are also in the mix at receiver.

De'Anthony Thomas is as explosive as they come with the ball in his hands, turning 42 carries into 338 yards and six touchdowns. Byron Marshall (196 yards, two TDs) and Thomas Tyner (80 yards, three TDs) also average more than six yards per carry.

While the high-octane offense was expected from the Ducks, owning the nation's fifth-ranked scoring defense was something few could have anticipated as the unit allows just 9.0 ppg on 319.0 ypg.

"We want to put pressure on the quarterback, whether its anxiety in terms of our looks or rushing the passer," Helfrich said of his team's defensive philosophy. "When you tackle well and don't give up those explosive plays that's how that happens."

Derrick Malone has a team-best 27 tackles, while Tony Washington has 3.0 TFL, 2.5 sacks and two forced fumbles. Dior Mathis had a 97-yard interception return for a touchdown versus Virginia, while Terrance Mitchell and Rodney Hardick also have picks.