SAN JOSE, Calif. (AP) -- San Jose State had an eight-point lead and a defense that had shut down No. 14 Boise State all day -- yet Spartans quarterback Adam Tafralis still felt uneasy as the fourth quarter ticked away.
"You don't count a team like that out," Tafralis said. "They're ranked where they are for a reason. They know how to win. They know how to come back."
He had plenty of reason to worry. With the cool of a seasoned conference champion, the Broncos staged a dynamite fourth-quarter rally that barely kept their unbeaten season and Bowl Championship Series hopes alive.
Jared Zabransky shook off three frustrating quarters and a draining illness to lead two scoring drives in the final minutes, and Anthony Montgomery kicked his third field goal -- from 37 yards -- as time expired in Boise State's 23-20 victory Saturday night.
Ian Johnson ran for 149 yards and a touchdown for the Broncos (10-0, 6-0 WAC), who stayed with Ohio State, Michigan and Rutgers as the only other unbeaten teams left in Division I-A. With two games left against Utah State and Nevada, the Broncos must win out to have a shot at getting to one of the five BCS bowl games.
For three quarters, Boise State seemed unlikely to remain perfect -- but Zabransky coolly led the Broncos through their stiffest test of the season against the much-improved Spartans (6-3, 3-2).
"He's a little sick, but he's fine," coach Chris Petersen said of his senior quarterback, who couldn't speak to reporters after going 14-of-20 for 181 yards in his 30th victory as a starter. "He only has so many games left as a Bronco. He'll be out there. If we don't make those plays he made in our passing game, we're in big trouble."
The Broncos have got themselves into plenty of trouble in recent years at Spartan Stadium: Two years ago, Boise State had to block a field goal as regulation ended in a double-overtime, 56-49 victory.
This time, Boise State faced its first halftime deficit of the season before falling behind 20-12 early in the fourth quarter on consecutive TD passes by Tafralis, who passed for 173 yards and three scores.
"I love this place. It brings out our competitive spirit," said Petersen, an assistant to Dan Hawkins in that crazy 2004 game. "Our competitiveness comes to the forefront in games like this. I knew they were going to handle it."
Indeed, Zabransky marched the Broncos on a 63-yard drive capped by his 1-yard TD sneak and a 2-point conversion pass to Jerard Rabb with 5:22 to play. San Jose State then stalled, and Marty Tadman's gutsy 44-yard punt return put Boise State at the Spartans 37 with 2 minutes left.
Zabransky and Johnson patiently moved the Broncos to the 20, and Montgomery's first game-winning kick of his life split the uprights. Players and coaches spilled onto the field to celebrate the Broncos' 37th victory in 38 WAC games.
"I don't remember the kick," Montgomery said. "I just remember running. It was all a big blur."
Not everything went well for Boise State in the final minutes: Johnson, the WAC's leading rusher, was sent to a hospital with an undisclosed injury to his abdomen or ribs after coming out of the game late in the fourth quarter.
James Jones caught two TD passes for the Spartans, who came agonizingly close to their first win over a ranked team since beating ninth-ranked TCU in 2000.
Still, San Jose State's rebuilding program under second-year coach Dick Tomey gained real legitimacy. Led by linebacker Matt Castelo's 20 tackles, the Spartans' defense held the Broncos' high-powered offense to fewer than 36 points for just the second time all season.
"We were short, and we have an empty feeling inside," Tomey said. "(The Broncos) are the ones that just keep finding ways to win, which I respect totally. We played against the Wicked Witch of the North, and we didn't win."
After the Broncos were shut out in the first quarter for first time this season, Jones caught a 10-yard TD pass on a fade to the corner on the first play of the second quarter. Boise State made drives of 86 and 61 yards before halftime, but had to settle for Montgomery's chip-shot field goals when they faltered at the goal line.
The Spartans also got their share of bad breaks: Yonus Davis made a 72-yard TD run early in the third quarter, but it was called back on an obvious holding penalty against Jones.
The Broncos finally executed near the goal line midway through the third quarter, with Johnson scoring on a 2-yard run on fourth-and-1 to finish off an 81-yard drive.
But San Jose State replied with a TD drive ending in John Broussard's 4-yard catch on another fade -- and after a kickoff-return penalty stuck Boise State back at its 6, Zabransky's awful pass was intercepted, setting up Tafralis' 3-yard TD pass to Jones with 14:20 to play.
