PROVO — Midway through the second half, with BYU leading by one, the shot clock was getting perilously close to zero, Jimmer Fredette had the ball at the top of the key and San Diego State's D.J. Gay was draped all over him.

Fredette had little choice but to raise up and try a shot. With Gay's hand in his face, Fredette readjusted the ball, sort of double-clutched in mid-air and watched as his 3-point try hit nothing but net.

"I was feeling good at the point and I kind of had that rocker step and he did a good job of guarding me," Fredette said. "But I was able to get the shot off and fortunately it went in. It was probably more luck than anything."

Luck or not, it was probably the turning point of the biggest game in Mountain West Conference history. Instead of SDSU ball down by one, the Cougars suddenly led by four and the Aztecs never got closer than four the rest of the way as BYU gradually extended its lead.

Fredette scored 43 points on the night with his usual array of shots and couldn't have done it under better circumstances with the eyes of the college basketball world focused on two Top Ten teams.

"He is as good of a player as I've ever coached against," said a shell-shocked San Diego State coach Steve Fisher. "That is a really good team led by a great player in Fredette."

Fredette certainly won the battle of the MWC's two best players, who both may be all-Americans and playing in the NBA next year.

The Aztecs' sophomore forward Kawhi Leonard finished with 22 points and 15 rebounds, but only made 8 of 20 from the field and finished with six turnovers on the night.

"Jimmer is a great player and they had a great supporting cast and great fans," Leonard said. "They're just a great team overall."

"He's got a lot of ways he can score and he showed us tonight," said SDSU backup guard James Rahon. "He's just a great player."

Fredette, who came in with a nation-leading 26.7 average, finished with his top scoring game in the Marriott Center, where a couple dozen media folks from around the country were on hand. He left with a 27.5 average and widened his lead as the nation's leading scorer.

Fredette started a bit slow after getting BYU's first basket on a layup two minutes into the game. With SDSU concentrating on Fredette and Jackson Emery, Brandon Davies took over and scored eight early points.

After making a guarded 3-pointer over Gay at the 12:10 mark, Fredette decided to take matters into his own hands as he scored 15-straight points the rest of the half.

He scored on a drive up the left side, then knocked down a 12-footer from the right baseline. With 4:29 left, he hit a 3-pointer from the right angle with Gay right in his face.

Next came a crossover dribble that left Billy White in one place and his shorts in another, followed by a pull-up jumper from 10 feet on the left side. He finally went to the foul line for BYU's first free throw of the half, with 1:50 left, but the 90 percent free throw shooter made just one of two.

Fredette put the Cougars up 30-26 with another crossover dribble drive on the left side that resulted in a layup, but came up short on a 60-footer at the end of the half.

The Fredette Show continued in the second half as he scored nine of BYU's first 12 points to stake the Cougars a 42-38 lead with 15:47 remaining.

He posted up inside for an easy basket, hit a pair of free thows, sank a 3-pointer from the right angle and then made a 10-foot runner in the lane.

It was 47-46 when he made his rocker-step, double-clutch, in-your-face 3-pointer from out front that gave BYU the needed momentum for its 20th victory in 21 games.

"He is just sensational," said Fisher, whose team gets another chance to see Fredette Feb. 26 in San Diego.