"I sure didn't see this effort coming," Sixers coach Doug Collins said. "It's kind of mind-numbing to me."
The Sixers lost their sixth straight game, their longest streak in nearly three years.
"I sure hope it can't get any worse than this," Collins said.
This latest defeat came against the Magic, who started two rookies and featured five rookies and three second-year players on their roster.
Orlando also entered this game having lost 28 of its last 31.
"I'm not going to sit here and drop my head," Turner said. "I don't think the leaders on this team will, either."
The Magic opened the third quarter on an 11-0 run and then began the fourth on a 17-3 spurt to go ahead 85-64.
"We kept the pressure on," Vucevic said. "We kept attacking and attacking. It was great to see that we were rewarded for our effort."
Harkless and Vucevic, who were acquired in the blockbuster four-team, 12-player Dwight Howard trade in the offseason, keyed the two runs for the Magic.
The Sixers received center Andrew Bynum in that trade, but the two-time All-Star has yet to play because of bilateral knee bone bruises.
Orlando is also dealing with its share of injuries, but it was hardly evident on this night. It played without guard Jameer Nelson (left knee) and forwards Glen Davis (fractured left foot) and Hedo Turkoglu (NBA suspension).
The Magic shot 51 percent in the first half, led by as many as seven points, and took a 47-42 advantage into the locker room.
From there, the Magic pushed the lead to 21 and wound up with a rare road win.
"We worked so hard for this and we hoped it would come," Harkless said. "It started with our energy and carried on through the team. We played with great intensity on defense and we made shots. It's just a great win and I'm happy for our whole team."
Magic F Al Harrington made his debut this season and scored nine points. Harrington had been dealing with sore knees. ... The Magic have unveiled 19 different starting lineups, tied for the most in the league. ... Sixers F Thaddeus Young reached double figures in rebounding for the second straight game since returning from a strained left hamstring. ... Sixers G Jrue Holiday had 10 assists. ... Vucevic registered his 32nd double-double.