The Jazz (31-26) will go into the All-Star break without any momentum having lost 13 of their last 17, still dealing with injuries and trying to find their way under a new coach.
The Warriors (26-29) have won three straight.
They did it despite an off night for star guard Stephen Curry, who was 1 of 7 on the night. His only basket came on a reverse layup that helped seal the win for Golden State.
The game was tied at 48 at halftime and at 76 through three quarters.
Ellis scored five straight to make it 99-92.
The Warriors made 8 of 19 3-pointers, while the Jazz shot 3 of 14.
Jefferson led the Jazz with 23 points, Paul Millsap added 22 and C.J. Miles 20.
Deron Williams continued to struggle. He was 5 of 13 and 1 of 5 from beyond the arc.
A power outage knocked out half of the overhead lights in the second quarter, and after a 2-minute delay, officials opted to keep playing, deeming it bright enough.
All of the lights were still not on when the Jazz went on a 7-0 run to start the second half.
Miles banked in a 3-pointer as the shot clock wound down then followed with a steal and dunk to give the Jazz a 55-48 lead. He gave Utah a 9-point lead, 61-52, with a driving layup with 8:27 left.
A pair of 3-pointers by Charlie Bell and Wright cut Utah's lead to 65-62 with 6 minutes left in the third.
Then it was Ellis' turn. He hit a 3-pointer and jumper to cut Utah's lead to 70-69 with 2:42 left in the third quarter.
Curry, who scored a game-high 27 points in a 96-81 Warriors victory on Jan. 30, had only two points at halftime. He started 0 for 6, including 0 for 3 from 3-point range.
Utah's Williams, who missed the first game against the Warriors because of a sprained wrist, entered Wednesday's rematch still lacking confidence in his shot. He was just 5 of 13 in Tuesday's loss to Phoenix, including 0 of 3 from 3-point range.
He came out more aggressive Wednesday and but missed two 3-pointers in the final minute.
Notes: Edgar Renteria, the 2010 World Series Most Valuable Player, attended Wednesday's game. ... With his eighth assist Wednesday, Utah's Williams became the fourth player in Jazz history to reach 4,000 career assists. ... Corbin said before the game that he selfishly hoped Williams would "shut it down" and rest his body rather than participate in this weekend's All-Star activities, but acknowledged he would simply tell his star guard to "be careful."