"Just a bad game from us as a team," Williams said. "... We had 17 turnovers and really didn't have much of a defensive effort in the third quarter, for whatever reason.
"We played decent in the first half, but our third quarter was about as bad as I've seen this team. We certainly can't play like that on the road against any team."
Anthony Morrow led the Pelicans with 26 points. Brian Roberts added 18. But All-Star Anthony Davis managed only eight points and six rebounds in 23 minutes.
Davis did not play in the decisive third quarter because of back spasms, which also sidelined him in Wednesday night's 137-107 loss at Denver.
Utah built a 73-65 lead heading into the fourth quarter, when Davis returned and the Pelicans rallied. But it was too late.
"I just took him out," Williams said. "... He wanted to play and I just said, 'No.' We're not in the playoffs ... [and] I've got to be smart. I just felt like he couldn't do what he wanted to do and didn't look good on the floor."
Despite the lackluster third quarter, the Pelicans gave themselves a chance. It was 96-93 with less than 10 seconds left when Tyreke Evans drove and dished to Darius Miller.
Wide-open in front of Utah's bench, Miller missed the tying 3-pointer.
"We drew up a play and it's one of the few times in an NBA game where you run the play perfectly," Williams said. "... We just missed an open look. "
Said Roberts: "That's exactly what we wanted. We had Tyreke with the ball, looking for shooters, and he found Darius. ... It was the best look we could ask for. It just didn't go in."