The 21-year-old Australian has flourished as point guard and had 14 points, 11 rebounds and 11 assists as his 76ers improved to 5-4 - their first winning record in nearly four years.
Simmons made five of his 13 shots but his poise and decision making in a closing 16-2 run, in which JJ Redick hit a trio of three-pointers, could not be faulted.
Redick scored 31 points and made eight of 12 from beyond the arc and said he has never heard a louder regular-season crowd in his 12-year career.
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"We all recognise the significance of tonight and getting over .500 for the first time in a long time," Redick said.
The veteran's shooting in the late stages even impressed his young teammate.
"He's amazing," Simmons, who was pretty amazing too, said.
Simmons has averaged 18.5 points, 9.6 rebounds and 7.9 assists in nine games, which includes six double-doubles.
Meanwhile, Patty Mills scored 17 points in the San Antonio Spurs' 108-101 win over Charlotte, while Joe Ingles had 11 points as his Utah Jazz went down 109-100 against Toronto.
Thon Maker got nine points and Matthew Dellavedova five for the Milwaukee Bucks in a 105-96 loss to Detroit.
