San Diego State coach Steve Fisher has been around long enough to have experienced plenty of tough losses.

This one was particularly difficult to digest.

He saw Chase Tapley, who carried the Aztecs for so much of the night against No. 3 Arizona, come off a screen and go uncontested toward the basket for what everyone thought would be a game-winning layup in the final of the Diamond Head Classic.

Nick Johnson changed everything, racing across to block the shot and preserve the Wildcats' 68-67 win over No. 17 San Diego State.

"It was incredible," Fisher said. "It looked to everybody's eyes that Chase was going to swirl it in. I watched it in the locker room on the replay, and he made a great play. He's a terrific athlete."

So ended a dynamic battle between two defensive-minded teams, which featured poor shooting in the opening half as players had to work for every shot, and one big play after another in a second half. The Aztecs (11-2) scored the first eight points of the second half and led by as many as eight points until the Wildcats (12-0) battled back behind Solomon Hill, who led Arizona with 21 points and was voted the tournament MVP.

Neither team led by more than two points over the final 10 minutes.

"We know we can play with any team in the country," said Tapley, who led San Diego State with 19 points and likely would have been the MVP if Johnson had not come out of nowhere at the last minute. "We showed it tonight. We just need to learn how to finish games."

A couple of streaks ended for San Diego State.

It had won its previous 12 games against current members of the Pac-12. Jamaal Franklin, its leading scorer, had gone 32 consecutive games in double figures. Franklin finished with nine points, and it was costly. He was fouled driving to the basket with 31 seconds remaining and missed one of his two free throws, which turned out to be the difference.

Johnson, however, was the biggest difference.

"It's the story of his bounce and his jumping ability," Tapley said. "He made one hell of a play. I just have to tip my hat off to him. I didn't even know he was around. He just came out of nowhere. I'm thinking the game is over, the next thing you know the ball is going off the backboard."

The Wildcats are off to their best start in 25 years, and it was their first win against a ranked opponent away from home in four years.

Mark Lyons drove to the basket on Arizona's final possession and was fouled, making two free throws with 13 seconds left for the final points of the game.

"It took two great plays on both offense and defense to secure the win," Arizona coach Sean Miller said. "And we made both of them."

The buzzer sounded during a scramble for the loose ball by the sideline.

"It hurts," Fisher said. "It's hard when you have a chance to win a championship, have a shot to beat an undefeated team, and you don't quite get it done, and you think you're going to do it right until the very last play of the game. It hurts badly."

Arizona won despite shooting only 37 percent from the field, including 5-of-20 on 3-pointers, though Miller was more impressed that except for an early spell of turnovers to start the second half that put his team in a hole, they didn't make careless mistakes and gave themselves plenty of looks.

"I don't think we had a bad shooting night," Miller said. "I think we played a great defense."

After turning the ball over just three times in the first half, Arizona had two turnovers that helped the Aztecs go on an 8-0 run to start the second period for a 35-29 lead. Franklin got his first points of the game on a pair of free throws, Xavier Thames made a 3-pointer, and Tapley converted a three-point play off yet another Arizona turnover.

After a sluggish, defensive battle, the pace and quality of the game picked up the rest of the way.

The Wildcats called a timeout trailing 41-33, and then went on an 18-9 run over the next six minutes to regain the lead. Hill was always in the picture, with some great hustle by Brandon Ashley, who scored inside and converted a three-point play on quick ball movement. Arizona regained the lead on Hill's two free throws, and he made two more with just under six minutes remaining for a 60-58 Arizona lead.

The game was tied six more times the rest of the way.

Kevin Parrom scored 17 points for the Wildcats, including a 3-pointer from deep on the baseline with 2:16 remaining that answered a 3 by Tapley. Johnson finished with 11 points for Arizona.

Arizona never trailed in the opening half, but after building a 16-9 lead on Johnson's 3-pointer, it never had control. That was to be expected from two defensive-minded teams, which have held their opponents to 38 percent shooting this season.

The Wildcats shot 29 percent in the opening half. The Aztecs missed their first seven shots. It was spirited, and it was sloppy. There were three missed dunks and badly missed layups in transition as both teams looked out of control at times.

Fittingly, the game was decided by a defensive play.

"It was very intense," Johnson said. "They're the No. 17 team in the country. We knew they were a good team coming in. We knew we would have to give it our all and stay in the game plan and in the end, it came up big."