Oregon is terrible on fourth down. The Ducks have converted on just seven of 18 fourth-down plays this year. Their 38.9 conversion rate ranks 10th in the Pac-12, behind struggling teams like Colorado and California.

We point that out because that's about the only thing Oregon isn't doing well right now.

The Pac-12 keeps track of 33 statistical categories, covering offense, defense, special teams, penalties, turnovers, etc. The Ducks rank first in the conference in 11 categories, including the two most important: scoring offense and scoring defense. They rank in the top three in 18 categories. Most of the categories they are not doing well in -- time of possession, onside kicks, opponent penalties -- evoke a "neh."

Others are deceptive. Oregon ranks sixth in total defense but is No. 1 in the far more revealing stat of average yards surrendered per play, where they rank eighth in the nation at 4.46 yards. The Ducks are 10th in red-zone offense, but their touchdown percentage in the red zone -- 72.1 percent -- ranks second.

This seems like a team with few, if any, holes. So what are the Ducks' weaknesses?

"I haven't seen any," said California coach Sonny Dyke, whose Bears lost 55-16 at Oregon on Sept. 28. "They are incredibly fast. I think the difference this year is they are throwing the ball so much better. Their receivers are faster, bigger, stronger, more physical, making more plays than in the past."

In the preseason, there were three questions about Oregon: 1. How would Mark Helfrich do stepping in for Chip Kelly? 2. What would be the pecking order at running back and how would De'Anthony Thomas be used? 3. How would the Ducks replace the dynamic linebacking troika of Dion Jordan, Kiko Alonso and Michael Clay?

Check, check and check.

The 7-0 record, No. 2 ranking in the national polls -- No. 3 in the BCS standings -- and 40-point average margin of victory suggest that Helfrich is doing fairly well. He might be a softer touch than Kelly -- though he's not afraid to tweak a reporter or two -- but he's not taking any mercy on the field.

Running back? The bottom line is the Ducks are No. 2 in the nation in rushing with 332.4 yards per game, 17 yards better than last year's average, and they've done that with DAT missing the last four games with an injury. Backups Byron Marshall and true freshman Thomas Tyner are both averaging 6.7 yards per carry and have combined for 16 touchdowns. Marshall, a sophomore, ranks 19th in the nation with 106.6 yards rushing per game.

Linebacker? Tony Washington, who replaced Jordan, has nine tackles for loss and 6.5 sacks. Jordan had 10.5 tackles for loss and five sacks in 2012. Derrick Malone leads the Ducks in tackles with 59. And, really, the bottom line is the defensive numbers, including a run defense that ranks 22nd in the nation.

"I think [the Ducks defense is] certainly the best they've been," Dykes said. "The secondary is really, really good. They are good at linebacker and they are pretty active up front."

Of course, Dykes is a first-year Pac-12 coach who hasn't been dealing with Oregon during its rise to consistent top-five team, though he was Arizona's offensive coordinator from 2007 to 2009. If we're going to ask whether this version of Oregon might be the best yet, we need to ask someone who's seen them all.

Washington coach Steve Sarkisian, whose Huskies have lost 10 in a row to Oregon, including five defeats during his tenure, let out a big breath when asked if this was the Ducks' best team.

"Hooof," he said. "We've played some pretty good ones. I think the balance they have on offense is probably the best that they've been."

The general consensus is Marcus Mariota is the Ducks' best quarterback during its recent run. He might, in fact, as former Ducks All-American QB Joey Harrington recently volunteered, be the best in program history. Mariota brings a dangerous downfield passing game to a longstanding dominance running the ball. As for the defense, it's very good, though it remains to be seen whether it's as good as the 2010 unit or even the talented crew of 2012 that battled numerous injuries.

Still, every coach who has played the Ducks probably feels there's something he wishes he might have attacked more or tried to exploit.

"I think there is a lot of places," Washington State coach Mike Leach said. "There's always a lot of places."

Washington State lost 62-38 at Oregon last weekend, with Leach's Cougars adding two late touchdowns to make the gap less dramatic. Quarterback Connor Halliday set a number of Pac-12 and NCAA passing records in the game -- he completed 58 of 89 passes for 557 yards -- but also threw four interceptions, one of which Terrance Mitchell returned 51 yards for a touchdown.

"Oregon is really fast," Leach said, echoing a common theme. "As you play Oregon, everything they do -- they can reel plays in quicker. They react to everything quicker. Very explosive... Oregon hits you in the mouth when you throw one up."

Of course, speculating on Oregon's seeming lack of weaknesses and its standing among other accomplished Ducks teams is a mostly a meaningless academic exercise when five regular season games remain ahead, including a visit Saturday from No. 12 UCLA. In fact, the next five Pac-12 games (combined opponent record of 26-7) are far tougher than the first four (combined record of 12-16).

Helfrich isn't really biting, either. When asked about areas of concern, he pointed back to the preseason questions and implied the jury is still out at linebacker.

Yet his overriding conclusion sounded very Chip Kelly-ish, while also offering plenty of room to read between the lines.

"I think everything," he said. "In every phase we can get better, starting with me, everything we do."

That's either coachspeak -- we need to get better every day -- or carries a more ominous implication: No weaknesses? Best Oregon team? You haven't seen anything yet.