Colorado is having perhaps the most surprising season in the country, but the toughest part has yet to come.

The No. 12 Buffaloes took care of business Saturday night as Sefo Liufau passed for three touchdowns and Phillip Lindsay ran for three as Colorado stayed atop the Pac-12 South with a 49-24 victory over Arizona in Tucson, Ariz.

Colorado (8-2, 6-1) stayed a half-game ahead of USC (6-2) and a game ahead of Utah (5-2) in the division. The Buffaloes, predicted to finish last in the division in a vote of the league media, have won more conference games this season than they did in their first five seasons in the Pac-12, when they won a total of five.

Next up are two home games -- No. 23 Washington State next Saturday in a surprising battle of Pac-12 division leaders before a regular-season finale against No. 15 Utah.

"This is a special time in Colorado football," coach Mike MacIntyre said. "Our young men have taken us from good to really good and hopefully next week they can take us to great."

Colorado led by as many as 32 points against Arizona, which entered with one of the worst defenses in the country at 37.1 points allowed per game.

The Buffaloes scored touchdowns on six of their first nine possessions. Lindsay, who ran 25 times for 119 yards, scored the first two touchdowns. Liufau connected on scoring throws of 15 and 27 yards to receiver Shay Fields, and a 40-yarder to receiver Jay MacIntyre, before scoring on a 1-yard run late in third quarter for a 42-10 lead.

Arizona (2-8, 0-7) has lost seven consecutive games for the first time since 2004.

The Wildcats moved the ball well, outgaining Colorado 417-388, but missed three field goals (44, 50, 44 yards) and hurt themselves with 13 penalties for 143 yards.

"We felt good moving the ball, we just didn't finish drives," Arizona coach Rich Rodriguez said. "Defensively, we gave up some silly stuff on third down, whether it was a penalty or a conversion. Just didn't execute when we had to."

Liufau completed 19 of 27 passes for 213 yards with one interception.

Arizona running back Samajie Grant, in his third game at the position after being moved from wide receiver, carried 16 times for 113 yards and two touchdowns. Arizona starting quarterback Brandon Dawkins was 9 of 19 for 107 yards, also running for 81 yards, before being replaced late in the third quarter by Anu Solomon.

Rodriguez lamented the injuries that have plagued his team this season and became animated when talking how kickoff man Edgar Gastellum suffered a concussion in practice last week when hit on the head with a football.

"It's hard to believe," Rodriguez said. "Somehow, it caused a concussion and he can't kick. That's a first. Are you kidding me? A kicker has a concussion. I mean, wow. You can't make this stuff up. I wish I was."

Colorado struck first with an 81-yard touchdown drive on its first possession after forcing Arizona to punt. The Buffaloes converted three third-down conversions on the drive, capped by a 1-yard run from Lindsay with 7:27 to go in the first quarter.

"We've really been leaving our defense out to dry the past couple of weeks," said Liufau, whose team had scored a total of 30 points versus Stanford and UCLA. "For the most part, we did well scoring points."

Arizona was turned away on the ensuing drive, missing a 44-yard field goal, but the Wildcats tied the game with an 85-yard drive that was their longest touchdown drive since going 94 versus Washington on Sept. 24. Grant took it in on a 2-yard rush, jumping over a would-be tackle at the line of scrimmage and scoring with 12:28 to go before half.

Arizona cut the lead to 14-10 with 8:22 left in the second quarter, but Colorado responded with two touchdowns before halftime and two more in the third quarter as it put the game away with 28 unanswered points.

NOTES: Colorado QB Sefo Liufau made his 36th career start, breaking the school record for quarterbacks held by current Buffaloes assistant Darian Hagan. ... Scouts from the Detroit Lions, New York Giants and San Francisco 49ers were in attendance. ... Saturday's game marked the eighth time an Arizona game started at 7:30 p.m. local time or later. ... Arizona senior WR Nate Phillips caught a pass for the 43rd consecutive game. ... Colorado LB Kenneth Olugbode had seven tackles in the first half, giving him 100 for the season. ... The Buffaloes have forced a turnover in 23 consecutive games, the longest streak in the nation.