Pascal Siakam had 25 points and 12 rebounds in his fourth game back since missing the beginning of the season recovering from shoulder surgery.
Isaiah Stewart added 20 for Detroit (3-9), who are last in the Eastern Conference.
The loss was the fourth in five games for the Raptors (7-7).
Neither team led by double digits through the first three quarters of the back-and-forth affair. A frenetic ending to the third quarter saw Banton steal the ball off fellow Canadian Cory Joseph twice in a row, finish with a huge dunk on one of them that brought the capacity crowd of 19,800 out of their seats.
The Raptors, wearing their black and gold city edition jerseys, took a 95-93 lead into the fourth.
But the Raptors fizzled in the fourth quarter, as Detroit hit five consecutive three-pointers – two by Grant – that put the Pistons up 117-106. The Raptors scored five straight points to pull to within six. Siakam converted a three-point play with 2:04 to play to slice the difference to just three.
Cade Cunningham, this season's No. 1 draft pick, shimmied to the hoop to make it a five-point game heading into the final minute. The Raptors missed four shots on their next possession, which all but ensured the loss as fans headed for the exits.
History was made late in the first quarter when five Canadians were on the floor at the same time – Raptors Banton, Khem Birch, and Chris Boucher, and Detroit's Joseph and Trey Lyles. Kelly Olynyk could have made it six, but the Pistons forward and national team veteran is out at least six weeks with a knee injury.
The Raptors were missing starting guard Fred VanVleet, who sat out with a groin strain that coach Nick Nurse said "has been bothering him for a little while." Seldom-used Dragic started in his place. Precious Achiuwa also missed the game with a sore shoulder.
Casey, meanwhile, has a young Pistons team this season, which presents some unique challenges.
"It's fun," said Casey, who coached the Raptors for seven seasons. He was fired after the 2017-18 season, the same season he was named NBA coach of the year. "For me it's exciting just for the fact that it is pure coaching. You want to pull your hair out sometimes because some nights guys make plays and the next night they don't recognize each other or a basketball. But it's exciting."
The Pistons hit their first five shots of the night to take an early eight-point lead. Trent Jr. had 13 points in the first quarter and his pullup jumper with 4:51 left in the period capped a 19-5 Raptors run that put them up by nine. The Raptors took a 34-31 lead into the second.
Neither team led by more than six points in a see-saw second quarter, and Lyles scored on a cutting dunk with 12 seconds to play and the Pistons took a 65-64 lead into the halftime break.
The Raptors were coming off a 115-109 win at Philadelphia on Thursday that snapped a three-game losing streak.
Banton was playing his fourth game in four nights, after playing for the Raptors 905 in Mississauga, Ont., on Friday.
"He played great," Nurse said of his G League game. "I think that we always had him in our plans to play some with the 905. He's carved out a role on this team maybe faster than anyone expected. It was a little bit of a tricky situation, playing four in four. He wanted to play. There were some things he wanted to work on. For the big picture, it's a good move for him and for his team."
The Raptors now head west for a six-game road trip that begins in Portland on Monday. They'll visit Utah, Sacramento, Golden State, Memphis and Indiana before returning home to host Boston on Nov. 28.
This report by The Canadian Press was first published Nov. 13, 2021.
Lori Ewing, The Canadian Press