PHILADELPHIA — Al Horford had no use for the premature celebration that showered confetti all over the 76ers’ home court at the end of regulation, delaying overtime and prompting an impromptu cleanup job. Turns out, Horford has the Celtics just a game away from a real sweep. Horford scored the go-ahead basket for Boston late in overtime in a wild Game 3 where the Philadelphia 76ers were sloppy with the basketball and the confetti, leading the Celtics to a 101-98 victory and a 3-0 series lead on Saturday night. “These are the kind of moments you want to be in as a basketball player,” Horford said. He saw some wild ones down the stretch. Marco Belinelli had hit a buzzer-beater to end the fourth quarter that sent the Sixers into a wild celebration on the court as confetti shot out of a cannon that made it rain over chunks of the arena. Hold up. Game 3 was only headed into OT. “I wanted to play right away,” Horford said.