Through the first 20 games of the season, the Detroit Pistons looked like one of the most improved teams in the NBA.

They are now in danger of falling below the .500 mark. They need a home victory over the streaking Boston Celtics on Saturday to avoid that distinction.

Detroit was cruising along with a 13-7 record but has dropped its last six games. The latest was especially agonizing, as it blew a seemingly comfortable fourth-quarter lead and fell to the Charlotte Hornets 108-107 on Wednesday.

The Hornets scored 13 unanswered points to erase a 10-point deficit. The Pistons tied it in the final minute before Hornets guard Jeremy Lamb made a game-winning last-second jumper.

"I think six minutes left in the game we were up 101-91 and I don't know if it was our offense going bad or their defense coming better, we struggled to score the ball in that situation and we've got to find easier shots," Pistons point guard Jose Calderon said. "And at the same time we didn't make those shots that we were making in the first. So yeah, we're going to look at the end, but it was just those plays, those last six minutes we just maybe didn't execute the right way."

The Pistons trailed most of the first half, then took the lead by outscoring Charlotte 38-22 in the third quarter. They were limited to 14 fourth-quarter points, and Pistons coach Dwane Casey felt his team may have gotten worn down.

"We missed some good looks in that stretch," he said. "You have to give Charlotte some credit. too, I thought defensively they buckled down. I go back to how we started. We had to exert so much energy to get back the lead but that is when the wheels fell off."

The Pistons' top players are healthy for Saturday's contest, but they're dealing with some injuries. Shooting guard Reggie Bullock has missed the last five games with an ankle sprain but is expected to play after practicing on Friday. Reserves Glenn Robinson III and Henry Ellenson are sidelined with ankle ailments.

The Celtics have already defeated the Pistons twice this season. They rolled at Little Caesars Arena 109-89 on Oct. 27, then won in Boston 108-105 three nights later.

Boston (18-10) has won eight straight, including a 129-108 victory over Atlanta on Friday night.

Center Al Horford is sidelined with a knee injury, which could present problems on Saturday as the Celtics try to contain Detroit's inside duo of Andre Drummond and Blake Griffin.

Boston was the preseason favorite to reach the NBA Finals out of the Eastern Conference and has found a groove.

"We expected things to come easy," guard Kyrie Irving told USA Today. "That's being part of team environment. Even the best teams had to go through trials of figuring out what they look like every day."

Coach Brad Stevens believes his team will continue to gain strength.

"We have all kinds of things we need to be better at," he told USA Today. "Our spirit is good. We're now more comfortable and focused on our tasks. Everybody knows what they need to do when they go in the game and know how we're going to play,"