EUGENE — At Oregon, speed is not just a gimmick. It's a way of life.

EUGENE — At Oregon, speed is not just a gimmick. It's a way of life.

Coach Mark Helfrich said the second-ranked Ducks are conditioned to go at a breakneck pace from their very first day in the program.

"In a practice situation, it happens with our young guys, especially our young skill guys, who are learning how to play without the ball or finishing the play downfield. In high school, they're adjusting their helmet, adjusting their facemask or their gloves," he said. "But they need to run back to the line of scrimmage and get set. We teach that just like blocking or tackling. It's a fundamental."

It's evident this season.

Two games in, 15 of Oregon's 17 touchdown drives have taken two minutes or less. The Ducks have more touchdowns than any team in the Pac-12, yet their time of possession has averaged only about 20:36. That's 118th among FBS programs.

The Ducks have had 18 "explosion plays" of more than 25 yards from the line of scrimmage, seven of which have resulted in touchdowns.

Granted, lower-division Nicholls State and Virginia did not really threaten Oregon in the first two games, but the Ducks (2-0) still rank second nationally with an average of 425 yards rushing a game, third with 664.50 in total offensive yards per game, and third with 62.50 points per game.

That quick-strike offense concerns Tennessee coach Butch Jones. The Vols (2-0) visit Autzen Stadium on Saturday.

"You can simulate the procedure, but it's hard to simulate the game speed of their athletes," Jones said. "It's one thing to get lined up fast, but it's leveraging the ball. It's containing the football. It's finishing plays."

Oregon's offense is guided this season by two forces, a mobile quarterback and a fleet-footed running back.

Sophomore Marcus Mariota has thrown for 422 yards and three touchdowns, and he's rushed for 235 yards and three more scores. He hasn't thrown an interception.

Last weekend in Oregon's 59-10 victory at Virginia, Mariota opened scoring with a 71-yard touchdown dash. He also threw two TDs, extending his string of at least one scoring pass in all 15 games that he's played. The streak ranks him third among active quarterbacks.

"For us, it's fundamental to our system. We want a passing quarterback that also happens to be a runner," Helfrich said. "We don't want a tailback that can kind of throw. We want to be able to dictate the game both ways."

Thomas has five touchdowns this season, tying him as the nation's scoring leader. For his career, the junior from Southern California who moonlights on the track team is averaging 1.4 touchdowns a game.

Both Thomas and Mariota have run for more than 100 yards apiece in both games this season. Mariota is the first Oregon quarterback to go over the mark in back-to-back games.

Tennessee linebackers coach Tommy Thigpen was Auburn's safeties coach in 2010 when the Tigers beat Oregon in the BCS championship game. He said the current Oregon squad is more explosive than the one Auburn faced, calling this season's Ducks "super-fast."

"They're making it seem like it's faster than it was in the past. The quarterback is probably one of the best athletes in America and their running back is probably the fastest player in the country," Thigpen said. "They have speed all over the field."

Helfrich took over as head coach of the Ducks this season after Chip Kelly — widely considered the architect of Oregon's so-called "blur offense" — left for the Philadelphia Eagles. Some wondered if the Ducks would experience a drop-off in speed with Kelly's departure. They haven't.

Helfrich is quick to point out, however, that the Ducks aren't all about pace. There's some finesse involved, too.

"We've never been a team that says, 'We need to snap it in 'X' seconds,' because there are certain things we are going to do at an almost frantic pace regardless of what the defense is showing us, and there's times we're going to need certain things — a certain technique or a certain coverage you want in the passing game," he said. "But I think when you're in a rhythm and everybody's playing with confidence and playing fast, you just kind of feel it."