Before Friday night, he hadn't played in the 76ers' last nine games, and he only saw two minutes of action in the first three quarters against Detroit.
The 14-year veteran changed things in the fourth, scoring eight points, including a go-ahead 3-pointer with 35 seconds left to help the 76ers overcame a 15-point second-half deficit to beat the Pistons 96-91.
Marshall was only active because Philadelphia was missing scoring leader Elton Brand, who strained his hamstring Wednesday night in a loss to the Los Angeles Lakers.
"My job is to come in and work hard in practice, and when my name's called, I'm ready to go," said Marshall, who had only played 20 minutes all season. "I stumbled a couple times, even when I was open, but I was able to get my feet set at the end."
Andre Miller led the 76ers with 19 points, and Louis Williams had 16, including 14 during the fourth-quarter rally.
"When you're down, you try to create a spark off the bench," Williams said. "We were playing with a lot of energy, we created some stops and that's how we got the win. It is a big win for us."
"We played three good quarters, but the fourth quarter is winning time and we didn't play well in the fourth," Iverson said. "I definitely want to win against that team, because I played with those guys for so long, but the reason this one hurts is because this game should have never come down to the end."
The 76ers trailed by as many as 15, but pulled ahead 82-81 on Marshall's jumper with 2:50 left. Detroit scored the next four points, but Williams picked off Iverson's pass and hit two free throws to put Philadelphia back in front with 55 seconds left.
"I was looking for someone on the perimeter and Lou Williams just made a great play," Iverson said.
Rodney Stuckey's 17-foot jumper restored Detroit's one-point advantage, but Marshall answered with a 3-pointer to make it 91-89.
"When we got up by two, it really lifted the guys, because it got us over that one-point hump," Marshall said. "This is huge."
Iverson missed at the other end, Rasheed Wallace's tip-in bounced off the rim, and Williams hit five free throws in the final seconds.
"I don't know why we don't have good concentration at home, but I didn't think we were as locked in as a team should be when they are up 15 at home," said Detroit coach Michael Curry. "We just didn't take care of the game."
- Detroit's Jason Maxiell picked up a technical foul for elbowing Reggie Evans in the ribs in the fourth quarter.
- Wallace was 0-for-2 from the floor in the first three quarters, despite playing 21 minutes.
- Sixers rookie Marreese Speights made his first career start in place of Brand.