"[Tuttle] played a great game, that's the best he's played all year," Mira Costa Coach Jon Reichardt said.
The Spartans' offensive struggles likely cost them the victory.
"Our defense was solid. When you only give up four or five goals in a game, you're putting yourself in a position to win," Lopez said.
La Cañada (28-8), the fourth-seeded team in the division, lead the entire match, except when it mattered most. Allen Moravati gave the Spartans a 1-0 lead with 1:44 left in the first quarter.
The Mustangs (22-8) scored with two seconds left in the first to tie the game at 1.
When halftime rolled around, the Spartans had a 3-1 lead after goals from Bo Mattix and Chase Borisoff in the second quarter.
Charlie Manclark cut the lead to 3-2 with the lone goal of the third quarter.
Trevor Roszkos pushed the lead back to 4-2 18 seconds into the final quarter. Jake Miller and Ryan Koverman scored two straight goals within a 1:07 to tie the score at 4.
The Spartans had four possessions in an attempt to take the lead, but they fell short, as the possessions resulted in two turnovers, a blocked shot and another shot that banked off the post during a La Cañada power play.
"We got a lot of open looks, we just couldn't put the ball in the cage," Lopez said.
After La Cañada turned the ball over with 24 seconds left, Mira Costa called a timeout and drew up a play. The play didn't work, but a foul gave Miller a chance to bury the game-winning goal, and he did, giving the Mustangs their first lead of the game, 5-4, with four seconds left.
Roszkos threw up a last-second shot more than half-way down the pool. The offering was on target, but Tuttle reached out and punched it away, giving Mira Costa the win.
"It was just a tough loss," Lopez said.
Reichardt said the game came down to defense.
"I thought both sides played very well," Reichardt said. "I think we missed a lot of good opportunities and I think they missed a few too. Our defense played better and that was the difference."
The last two games between the Spartans and the Mustangs were significantly higher scoring. Mira Costa won the first match on the road 17-9, and lost the second meeting between the teams 9-8, at home during the Hank Vellecamp Tournament.
"You never know in a CIF game," Reichardt said in response to the low-scoring game. "When two teams aren't playing well offensively, it comes down to the defense and that's what happened."
La Cañada's offense went relatively silent after defeating Beverly Hills, 15-4, in a first-round playoff match Nov. 10.