BOISE -- Fourteenth-ranked Boise State kept its perfect season alive by surviving a wild Thursday night contest on the blue turf of Albertsons Stadium.

Star tailback Jeremy McNichols scored twice and racked up 249 yards from scrimmage as the Broncos held on for a 28-27 victory over BYU.

Boise State (7-0) overcame a season-high five turnovers, then survived by blocking a field goal with 15 seconds left -- and denying two additional desperation BYU offensive plays because the kick occurred on second down and was recovered by the Cougars.

"Our leaders in the huddle told us, 'Everyone is watching. Who is going to make the big play?'" said Boise State defensive tackle David Moa, who blocked the potential winning kick. "We got a great push up the middle, and (the ball) hit me right in the hand."

McNichols gained 140 yards on 30 carries -- including a go-ahead, 4-yard touchdown with 10:37 remaining -- while adding 109 yards and another score on five receptions. Boise State quarterback Brett Rypien completed 25 of 39 passes for 442 yards and three TDs, helping overcome two pick-sixes by the BYU defense.

"To lose the turnover battle by five and win is very rare, and we've got to clean that up as an offense," McNichols said. "But every play has its own life. We just continued to claw and fight our way through."

BYU (4-4) was outgained 571-322 in total offense, but the Cougars hung tough by scoring the two defensive touchdowns and blocking a field-goal attempt in the first quarter.

"I thought we gave up way too many yards and a lot of big plays," BYU coach Kalani Sitake said. "We were able to create some turnovers and disruption and get some (defensive) scores but ... there were a lot of things we could have done better in all three phases."

Quarterback Taysom Hill threw for 187 yards, ran for 48 and scored the only offensive touchdown for BYU, which got interception return TDs from Fred Warner and Dayan Lake. The Cougars' four losses this season have come by a combined eight points.

"We've battled through a lot of adversity," Warner said. "We fought this game, and I'm proud of our guys, but these (close losses) hurt the most."

Boise State was on top 21-17 at the half, but BYU recaptured the lead by scoring the only points of the third quarter. After the Broncos turned it over on downs, Hill capped a 58-yard drive with a 1-yard run to make it 24-21.

Turnovers continued to plague Boise State, with Akilian Butler muffing a punt and Thomas Sperbeck losing a fumble to bring the count to five through three quarters.

The Cougars cashed in the Sperbeck fumble, with Rhett Almond kicking a 37-yard field goal to make it 27-21 in the opening moments of the fourth.

Boise State responded by mounting a gutsy, 90-yard drive, with McNichols barreling in to reclaim the lead. The one-point margin would stand after Moa's blocked kick and two incompletions by Hill, including a Hail Mary heave to the end zone as time expired.

BYU scored its two defensive TDs in the first half, but Rypien countered with 317 yards passing and three TDs as the Broncos took a four-point lead into halftime.

Boise State started with a bang. On the third play from scrimmage, Rypien motioned McNichols out of the backfield and fired a perfect strike deep down the middle of the field for a 76-yard touchdown.

After a BYU punt, the Broncos quickly marched 58 yards in eight plays, capped by Rypien's 12-yard strike to Sperbeck for a 14-0 lead. Sperbeck wound up with nine catches for 109 yards.

BYU punted again, and the Cougars were reeling after a 56-yard completion from Rypien to Sean Modster. But three big plays by the BYU defense changed the complexion of the game.

The first was a blocked field goal, with a long return that set up an Almond field goal to trim the deficit to 14-3.

On the next play from scrimmage, Warner stepped in front of a deep Rypien pass, tiptoed along the sideline and broke multiple tackles on his way to a 59-yard touchdown return.

Late in the second quarter, the BYU defense struck again, with Lake grabbing a tip-drill interception and racing 50 yards untouched to put the Cougars on top 17-14.

BYU forced a third first-half turnover when McNichols fumbled after a long run, but the Cougars turned it back over on downs. Rypien responded with a perfectly orchestrated two-minute drill, firing a 36-yard bullet to a leaping Cedrick Wilson to give the Broncos the halftime lead.

NOTES: BYU starting RB Jamaal Williams did not enter the game because of an ankle injury, though he was in uniform on the sideline. Williams leads the Cougars with 165 carries for 942 yards and 10 touchdowns. ... BYU also was missing starting RT Thomas Shoaf and DT Merrill Taliauli. ... Boise State played without starting RT Mario Yakoo ... WR Thomas Sperbeck set a Boise State record for career receiving yards on a 20-yard grab in the first quarter. The previous record of 3,063 yards was held by Titus Young, a second-round NFL draft pick in 2011.