San Diego » If the NCAA Tournament selection committee gives points for degree of difficulty --- a lot of which the Cougars brought upon themselves Tuesday night -- BYU just might have punched its ticket to the big dance with a brilliant second-half performance against the San Diego Aztecs.

Overcoming a 13-point halftime deficit -- just as UNLV did to it a month ago -- and a raucous crowd of 9,631 at Cox Arena, BYU rolled past the stunned home team 69-59 to keep alive its hopes of at least sharing a piece of the Mountain West Conference title.

"That was an absolutely huge win," BYU guard Jimmer Fredette said. "We had our backs against the wall, and we needed to win that game."

Fredette scored 20 of his game-high 28 points in the second half, which tied a career high, while Jackson Emery added 12, including a huge three-pointer when the Cougars made their clinching run in the final seven minutes.

"We played a great second half," said BYU coach Dave Rose. "We came out in the second half with a determined look. … The guys regrouped [after a miserable first half] and we just had a different look to us that second half."

It was BYU's first win here since 2003, and it couldn't have been sweeter, given how lethargic the Cougars looked in the first half, and how much was at stake.

BYU improved to 9-4 in league play, 21-6 overall, while the Aztecs fell to 8-5, 18-8 overall, and out of the tie for second place in the league standings.

The Cougars are now tied with New Mexico for second, with league-leading Utah visiting on Saturday.

The Aztecs scored 21 of the final 23 points of the first half to take a 33-20 lead at the break, and the Cougars walked off the floor looking as if they could start making plans for the NIT.

Fredette said Rose "got into us a little bit" at halftime, and the Cougars turned it around offensively while a zone defense puzzled and then stifled the Aztecs, who shot 43 percent in the second half and committed nine turnovers after the break.

The unquestioned leader of one of the most significant comebacks in BYU basketball history was Fredette, the sophomore from Glens Falls, N.Y., with the baby face and gunslinger's heart.

"Things were going great," said Fredette, smiling all the way. "We knew we had this game, once we got our game going."

With the Cougars trailing 55-52 and their hopes dim because senior Lee Cummard was on the bench with four fouls, Fredette simply took over. He scored nine straight points to give the Cougars a 61-55 lead with 1:47 left, and the Aztecs were finished.

Fredette's big blow was a three-pointer with 3:28 remaining, and the Cougars were 7-for-8 from the free-throw line down the stretch.

"It is a huge win for this [particular] game," Rose said, noting that freshman Noah Hartsock played a key role off the bench.

drew@sltrib.com