Jordon Brookshire's last competitive pass had been thrown in mid-October, back when he lost San Diego State's starting quarterback job and got labeled a third-stringer. He was not a likely candidate to save the Aztecs' Mountain West championship hopes in their regular-season finale.

With their offense sputtering and even their vaunted defense struggling to slow down Boise State late in the first half, the Aztecs turned to Brookshire out of desperation and necessity.

Four drives and four scores later, San Diego State was rolling toward a historic victory.

Brookshire led No. 22 San Diego State to 24 unanswered points after replacing Lucas Johnson late in the first half, and the Aztecs claimed the conference's West Division title with a 27-16 victory over the Broncos on Friday.

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

Brookshire passed for 192 yards and a touchdown for the Aztecs (11-1, 7-1), who celebrated at their temporary home in the Los Angeles suburbs after completing their first 11-win regular season in 99 years of football.

"It feels great, and it’s been a while since something like that has happened," said Brookshire, who capped the scoring with a 16-yard TD run through the heart of Boise State's defense. "It’s a real confidence-booster, and I feel so grateful to be around this group of seniors and to be able to pull this off for them on their day."

The Aztecs, who have never had a 12-win season, will host the Mountain West title game next Saturday, Dec. 4, against Mountain Division champ Utah State (9-3, 6-2).

San Diego State erased an early 13-point deficit with a bounce-back effort from its vaunted defense, which shut out the Broncos (7-5, 5-3) over the final 38 minutes.

Jesse Matthews caught nine passes for 133 yards, and Greg Bell rushed for a touchdown — but Brookshire transformed the struggling San Diego State offense when he took over on the penultimate drive of the first half. On their next four drives, the Aztecs turned a 13-point deficit into an 11-point lead.

Aztecs coach Brady Hoke said he inserted Brookshire primarily because Johnson was "banged up," but Brookshire immediately showed it was the right decision.

"There’s no question about it," Hoke said. "Coming out after halftime there was an energy that may not have been there earlier, and you could really feel it. I also think we got on our heels a little bit in the first half defensively, and then that wore off."

Kurt Rafdal and Khalil Shakir caught early TD passes from Hank Bachmeier for the Broncos, whose four-game winning streak ended. Boise State has its first five-loss season since 2013 under first-year head coach Andy Avalos, a native of nearby Corona, California.

"For some reason, we just couldn’t execute and finish the game out, but everybody fought their hearts out," Shakir said. "We did everything we could to go against one of the best defenses in the country."

Patrick McMorris made two of the Aztecs' three interceptions, and Jonah Tavai got three of their four sacks while the defense harassed and hit Bachmeier throughout the second half, forcing backup Jack Sears to play the final two series.

Brookshire began the season as the Aztecs' starting quarterback, but Johnson took over after two games when Brookshire injured his foot. Brookshire returned and struggled through two more starts before Johnson reassumed the starting job for the next six games, with Brookshire bumped to the third string behind freshman Will Haskell, who wasn't in uniform Friday for reasons Hoke wouldn't disclose.

"A lot of my coaches just say I’m a fighter, and I think that’s been present," Brookshire said. "In life, things don’t always go the way you want them to, but what matters is how you respond to those things."

Johnson was 9 of 20 for 98 yards when Brookshire relieved him and immediately led the Aztecs 78 yards for their first TD on Matthews’ 29-yard catch-and-run. Brookshire strung together another quick drive ending with Matt Araiza's 37-yard field goal 3 seconds before halftime.

The Aztecs went ahead 20-16 to open the second half on a 75-yard drive that included a third-and-11 conversion and two fourth-down conversions, including Bell's 2-yard TD run. McMorris' second interception then led to a drive ending in Brookshire's TD run.

"We’ll digest this, think about and look at the things we need to fix," Broncos linebacker Kekaula Kaniho said. "But we know we’ll have one more opportunity to finish this season, and we’re excited to do that."

THE TAKEAWAY

Boise State: A team that scored 128 points in its last four games got off to a strong start against the conference's best defense, but couldn't sustain it. The Broncos aren't alone in struggling against the Aztecs' heavy hitters, but it's a regular season-ending disappointment after an encouraging stretch under Avalos.

San Diego State: The Aztecs earned one more game with their unlikely homefield advantage at Dignity Health Sports Park. San Diego State has spent the last two seasons playing 116 miles northwest of campus on the LA Galaxy’s home field while the $310 million Aztec Stadium is being constructed for a 2022 opening on the site of the demolished Jack Murphy Stadium in San Diego’s Mission Valley. The Aztecs are 9-2 in Carson, including 6-1 this year.

UP NEXT

Boise State: Probable bowl game.

San Diego State: Mountain West title game against the Aggies on Dec. 4.