Josh Scott scored eight of his 19 points in overtime to help Colorado beat Washington State 71-70 Wednesday night.
"We just did not play Colorado basketball tonight," Boyle said. "We better play better on Sunday.
"We've got a target on our back now," Boyle said, referring to the Buffaloes' ranking. "Our guys proved we are not ready to handle that yet."
Boyle did praise Scott, who also had nine rebounds. The forward called the close game a "wake-up call," but also wanted to keep some perspective.
"We've got to be optimists here, at least we won," Scott said. "Even on a bad night, we won."
Askia Booker added 18 points for Colorado (14-2, 3-0 Pac-12), which has tied the second-best start in program history. Xavier Johnson scored 14 for the Buffaloes, who shot just 41 percent and trailed for much of regulation. Leading scorer Spencer Dinwiddie was held to six points, nearly 10 below his average.
"I don't know where Spencer was," Boyle said. "Spencer wasn't in the Spokane Arena tonight."
Dexter Kernich-Drew scored a career-high 24 points to lead Washington State (7-8, 0-3), which was playing without leading scorer DaVonte Lacy, out with a rib injury.
Colorado dominated the free-throw shooting, making 26 of 38, while Washington State went to the line only three times, making them all.
Washington State's Que Johnson hit a 3-pointer to send the game into overtime after sitting much of the second half because of foul trouble.
"When they call your name, you've got to be ready," Kernich-Drew said of Johnson.
Colorado got consecutive baskets from Scott, Dinwiddie and Scott again for a 62-58 lead. Johnson scored for Washington State, but Scott replied with two baskets to make it 66-60.
D.J. Shelton's long jumper cut Colorado's lead to 66-62 with 1:37 left.
Booker made two free throws for Colorado with 37 seconds left. Junior Longrus stuffed the ball for Washington State, but the Cougars were forced to foul.
Booker made two more free throws, but Shelton replied with a 3-pointer to cut it to 70-67.
Dinwiddie made one of two free throws, and Washington State's Royce Woolridge sank a 3-pointer to cut Colorado's lead to 71-70 with 1.5 seconds left.
With 0.3 on the clock, Dinwiddie missed both free throws, and a desperation heave by Shelton missed as time expired.
The game was quite a turnaround for Washington State, which was routed 60-25 at No. 1 Arizona six days ago.
Woolridge said the team has bought into the message from coach Ken Bone.
"He's telling us to play together and play as a team," Woolridge said. "We did some soul-searching and we know who we are now."
Woolridge had 10 points and 11 assists in an unusual double-double. Shelton had 14 points and 12 rebounds, while Johnson finished with 10 points. The Cougars shot 45 percent, including 13 of 23 from 3-point range.
"We've got some guys that can make shots," Bone said. "Fortunately tonight we made them."
Washington State led 34-28 at halftime.
Colorado took its first lead of the game when Xavier Johnson made two free throws for a 53-51 lead with 4:26 left.
Xavier Talton hit a 3 to give Colorado a 56-53 lead with 1:20 left. Woolridge missed a 3 on the other end.
Colorado brought the ball down and Booker missed a jumper. Washington State rebounded with 20 seconds left and called timeout with 10.3 seconds left.
Que Johnson hit a 3-pointer from the left side with a couple of seconds on the clock to tie the score at 56. Booker missed at the buzzer to send the game into overtime.
Colorado is enjoying its highest poll ranking since the 1997 team also reached No. 15.