The 'Phenomenal One', making his fifth appearance on his latest comeback from injury, also completed the full 90 minutes for the first time in a Corinthians shirt.
Ponte Preta went ahead in the 32nd minute when they sprang the Corinthians offside trap and Leandrinho chipped the ball over Felipe.
Corinthians equalised four minutes later when Ronaldo won and converted a penalty, his third goal for the club.
The high point came in the 58th minute with a superb Ronaldo goal, when he collected a cross with his left foot, slipped inside his marker and placed the ball in the far corner.
With Ponte Preta down to 10 men after Edilson was sent off for a second bookable offence, Corinthians looked set for victory.
However, the visitors equalised in the 75th minute when Corinthians failed to cut out a cross and Gum headed in.
Corinthians stayed second in the table with 34 points from 16 games and comfortably on course for a semi-final place.
The Paulista is the largest of the regional championships which kick off the Brazilian season.
Seventeen-year-old striker Neymar was on target as fifth-placed Santos beat Santo Andre 3-0, scoring the third goal with a cool finish after Madson broke down the right and pulled the ball back.
Madson scored the first goal in the 18th minute and Triguinho was also on target before the break.
