"It was the easiest shot I had all night," said West, who had missed seven of his previous nine shots. "That was a gimme. I had to hit that."
Pierce drove the lane with time winding down and kicked the ball to a wide-open West, who knocked down a 20-footer.
"In past years I would have maybe taken a bad shot or tried to go through people," Pierce said. "Once I saw they collapsed on me, I needed to trust my teammates. That is what better players in this league do."
Gomes had 10 points, 12 rebounds and a career-high 10 assists for the Celtics.
"I don't even think I had a triple-double at Providence, maybe in high school," Gomes said.
Brevin Knight, who finished with 22 points, missed a jumper with 7.6 seconds left in overtime for the Bobcats, who are 0-5 in Boston.
"When a great player makes the correct play, and another good player knocks down the shot, you tip your hat and move on," Knight said.
Gerald Wallace tied it at 100-all with 10.5 seconds left in regulation after Sean May's shot was blocked by Theo Ratliff and on his second rebound, Wallace laid it in.
Pierce's 18-foot jumper as regulation time expired clanked off the side of the rim.
Emeka Okafor continued his strong comeback after playing in only 26 games last season with 28 points and a career-high 18 rebounds.
"You can sing the whole song about how we fought, but we want the win," Okafor said. "We've done this enough times."
Boston overcame 25 turnovers to avoid starting the season 0-4 for the first time since 1969-70.
Pierce grabbed 13 rebounds, but had a Celtics' franchise-record 12 turnovers.
Szczerbiak scored 20 points in the third quarter on 6-of-7 shooting, including four 3-pointers, as the Celtics outscored Charlotte 37-25 to take an 82-74 lead after three. He had 33 points in Boston's last game against Washington.
Othella Harrington's fallaway jumper capped a 13-5 run and tied it for Charlotte at 87-87 with 5:16 remaining.
Boston trailed 24-17 after the first quarter while shooting 7-of-23 from the field with eight turnovers.
The last four games between the Celtics and Bobcats have been decided by three points or less.
- Celtics forward Al Jefferson is expected to miss at least two weeks after having his appendix removed.
- Raymond Felton left the game with a strained back and did not return for the Bobcats.
- Cedric Maxwell had the previous Celtics record with 11 turnovers in 1978 when they began keeping the statistic. Szczerbiak had a career-high 22 points in a quarter in 2003.
- Boston used its fourth starting lineup in four games.