WACO, Texas -- A watered-down version of Baylor's regular offensive machine still did the job against Iowa State.

Second-ranked Baylor raced to a big first-quarter lead despite a drenched playing field, then sloshed the rest of the way to a 45-27 victory over the Cyclones on Saturday at McLane Stadium.

The Bears, who gained 485 yards, fell well short of their 719-yard average.

Baylor and Iowa State kicked off on a soggy morning. In the 24 hours leading up to kickoff, more than six inches of rain had fallen in the Waco area.

The wet field and ball seemed to affect Baylor quarterback Seth Russell, who completed just 16 of 37 passes for 197 yards. But he threw two touchdown passes and ran for 64 yards and a score to help keep Baylor afloat and alive in the College Football Playoff race.

Baylor coach Art Briles said he thought the Bears struggling in the middle of the game was a result of a lack of focus and intensity.

"I just don't think we had the energy -- I could feel it coming out at halftime -- that we had starting the game," Briles said. "And that's my fault. And when you look at things from a reality standpoint, if you're up 35-7, they can add. We felt like we were in pretty good shape; but, in this league, you're really never not."

Most of Russell's and Baylor's big plays came in the first 22 minutes, when the Bears (7-0, 4-0 Big 12) surged to a 35-0 lead.

But then Baylor didn't score for more than 32 minutes of game time. Iowa State (2-5, 1-3) won the intervening period, 21-0, but the Cyclones couldn't come all the way back.

Iowa State made it 35-20 when quarterback Joel Lanning hit wide receiver Jauan Wesley for a 4-yard touchdown with 7:47 left. But the Cyclone's ensuing onside-kick attempt didn't travel 10 yards.

Baylor took over and drove for a field goal to break its scoring drought.

Lanning completed 12 of 17 passes for 144 yards and three touchdowns to lead the charge. Iowa State running back Mike Warren finished with 145 yards on 28 carries.

"The defense played great in the second half and the offense just kept chipping away," Lanning said. "When you're down 35-0 or whatever it was, you don't really think about it. You've just to come out and start chipping away at the game."

Baylor put Iowa State in a 21-point hole early.

After Russell tossed a 36-yard touchdown pass to Coleman on the Bears' game-opening possession, Iowa State appeared to have some offensive traction.

Cyclones quarterback Sam B. Richardson hit wide receiver Quenton Bundrage for a 9-yard gain and running back Mike Warren rushed six yards for a first down to the Iowa State 39. But two plays later, Warren fumbled and Baylor nickel back Travon Blanchard recovered at the Bears' 48.

By the time Iowa State gained its next first down, four possessions later with less than three minutes left in the first quarter, Baylor led 21-0 and Iowa State had little hope of making it close.

"We came into this with the goal of zero turnovers," Iowa State coach Paul Rhoads said. "To win a game like this, you can't give them the ball back. They make a living out of three-and-outs on defense and takeaways and scoring fast. The next thing you know, you're buried. It was 21-0 in a hurry."

The Baylor defense took the ball away from the Cyclones three times in the first half -- Blanchard's fumble recovery and interceptions by cornerbacks Xavien Howard and Ryan Reid -- and the Bears held Iowa State to 135 yards before halftime.

"Of course, turnovers are always big, getting the ball back to our offense, especially in conditions like today," Blanchard said. "With a lot of rain, the ball is slippery, so the conditions were favorable to get turnovers, strips and interceptions and getting the ball into our offense's hands. The more time they have the ball, the better. That's big."

Baylor's offense did its usual damage in the same time period, gaining 377 total yards in the first half.

Russell broke loose around the left side, juking one Iowa State defender and waltzing into the end zone for a 37-yard touchdown that put Baylor ahead 14-0. He hit running back Shock Linwood for a 6-yard touchdown pass early in the second quarter that put Baylor ahead 28-0.

Bears running back Devin Chafin scored on a 2-yard run to put Baylor ahead 35-0 with 8:14 left in the second quarter. With that, the Bears safely shifted into coast mode.

Iowa State began cutting into Baylor's lead midway through the second quarter. Lanning led a 75-yard touchdown drive, keyed by running back Joshua Thomas's 42-yard run. Thomas capped the march with a 2-yard touchdown dive with 4:49 left in the half.

"That drive was a pivotal point for us from an energy level," Rhoads said. "With that drive, our whole sideline, our whole football team picked up and responded. The momentum that we received from that drive was what it was and Joel certainly does deserve some credit for his performance."

NOTES: Iowa State has lost 14 straight vs. ranked opponents. The Cyclones last defeated a ranked foe on Oct. 6, 2012, when they won 37-23 at No. 15 TCU. ... Baylor has won 20 consecutive home games, the longest streak in the nation. The Bears last fell at home vs. TCU, 49-21 on Oct. 13, 2012. ... Coming into this week, Baylor led the nation in total yards, averaging 719.7 per game -- 96 more than second-place Texas Tech.