— LONDON  — Halftime ended. Showtime began.

The U.S. men’s Olympic basketball team needed a while but eventually put on the show fans came to see, beating Tunisia 110-63 on Tuesday night.

Finally pulling away when coach Mike Krzyzewski started the reserves to open the second half, the Americans had six players in double figures and improved to 2-0 in the tournament.

Krzyzewski insists he planned to start the second unit even before a lackluster first half, and said he there was nothing bad about the Americans’ performance.

“It’s not going to a perfect thing, you know?” he said. “But overall tonight was good. I mean, come on, it was 110-63.”

True, it was a 47-point blowout, but the lead was just 13 at the half and he sure didn’t look pleased as he walked quickly to the locker room. But if he didn’t see anything wrong, the players sure did  —  though they weren’t concerned.

“We told him, don’t get worried,” Carmelo Anthony said. “We’re all right.”

They sure were.

Anthony, Deron Williams, Russell Westbrook, Kevin Love and Andre Iguodala opened the third quarter with a 21-3 run, turning a surprisingly close 13-point lead into a 67-36 bulge before any of the more celebrated starters finally got to play in the second half.

“That was a great lift, man. That’s the best thing about this team, there’s no drop off,” said Kevin Durant. “We’ve got All-Stars off the bench. Those guys did great job for us.”

Anthony and Love scored 16 points apiece for the Americans, who gave the fans the dunk show they expected once the game was in hand. Durant had 13 and rookie Anthony Davis dunked his way to 12.

Makram Ben Romdhane scored 22 for Tunisia, the African champion playing in just its second Olympic game. A wire-to-wire loser Sunday against Nigeria, they’ll be able to tell their kids their first Olympic lead came against the powerful Americans.

“They could have absolutely have taken us to the cleaners but Coach K’s discipline made sure that didn’t happen,” Tunisia coach Adel Tlatli said through an interpreter.

Tunisia began fearlessly, with Ben Romdhane driving all the way for a dunk to take an 8-4 lead. Tunisia still led by three with 2:39 left in the period before the U.S. second unit ran off the final nine points for a 21-15 advantage.

The Americans missed all eight 3-pointers in the first, even worse than their 0-for-6 start Sunday, before Anthony nailed one to open the second quarter. Westbrook followed with a jumper for a 26-15 lead, and the expected U.S. blowout seemed to be under way.

Instead, Marouan Kechrid made consecutive 3-pointers a couple of minutes later that brought Tunisia within six points, and he made another one with about 3 Ω minutes left, pumping his fist back toward his bench after cutting the U.S. lead to 35-30.

Only then did the Americans finally get control of the game, rattling off 11 straight points, with James’ behind-the-back pass to Durant for a dunk making it 46-30. The Americans led 46-33 at the half.

The teams met in the 2010 world championship in a similar game. The U.S. won 92-57, pulling away after leading by just six at halftime and holding the Tunisians to 27.8 percent shooting for the game.

Westbrook scored 11 for the U.S., which plays Nigeria on Thursday.