LEXINGTON, Ky. - Kentucky coach John Calipari knew the hangover was coming. And he knew he couldn’t stop it.

So rather than yell and scream after the third-ranked Wildcats slogged through the first 20 minutes against Long Beach State on Wednesday, less than 48 hours after celebrating the program’s 2,000th win, Calipari simply challenged his players to shake it off.

“I’ve done this so long, there are certain things that you can expect,” Calipari said. “On the game before Christmas following the 2,000th win where there is a celebration and people are going nuts, there is going to be a little bit of a letdown.”

It only lasted a half.

The Wildcats took control late for a gritty if not exactly pretty 86-73 win, wearing down the 49ers in the second half to continue the program’s best start in more than 30 years.

“We were able to grind it out, execute it to a T down the stretch,” Calipari said.

The Wildcats (13-0) had to after the 49ers kept hanging around. Long Beach State (6-6) pulled within 58-55 with just over 11 minutes remaining before Kentucky finally asserted itself behind freshmen stars John Wall and DeMarcus Cousins.

Wall finished with 19 points while Cousins shook off early foul trouble to score 15 points and grab 10 rebounds in his sixth double-double of the season.

“He was the best player on the floor,” Calipari said.

The trouble was keeping him in the game.

Cousins played just over two minutes in the first half after getting a personal foul and a technical foul after getting tangled up with Long Beach’s Larry Anderson.

“He’s still got a lot of growing up to do,” Calipari allowed.

Cousins spent the rest of the half watching from the bench, and was soon joined by Wall and junior forward Patrick Patterson.

Their absence allowed the 49ers to scrap to a 37-all tie at the break.

Even when the trio returned to start the second half, it took time for Kentucky to assume control. Long Beach even took the lead 46-44 on a putback by T.J. Robinson before the Wildcats started to wake up.

Eric Bledsoe, playing on a sore ankle, hit a 3-pointer to put Kentucky ahead, and Wall followed with a couple of free throws. The 49ers rallied to tie it at 51 before Kentucky’s defense started to wear on them. Long Beach was playing its second game in just over 36 hours, having taken the redeye on Monday night following an 85-80 overtime loss to Loyola Marymount.

“They died at the end and they should have,” Calipari said.

Having a focused and energized Cousins certainly helped. The 6-foot-11 center sparked a 12-4 surge with the kind of energetic play that has gotten him into trouble at times.

Timeline Must-see college hoops games From the Duke-Butler rematch to the Bluegrass State Showdown, here are the games you have to watch. NBCSports.com

He managed to keep his emotions in check enough in the second half to help Kentucky continue its best start since winning the first 14 games of the 1977-78 season, which it capped with a national championship.

“When (Cousins) sets his mind to being a beast, you see what he can do,” said Kentucky forward Ramon Harris.