Midfielder Felipe Bastos equalised in the 78th minute after central defender Paolo Goltz had put Lanus ahead in the 57th, also with a free kick.
"He hits it like the gods," said Lanus goalkeeper Agustin Marchesin of Bastos's equaliser after Ponte Preta had been awarded a free kick on the edge of the box.
"He did the same with another free kick but I managed to tip it on to the bar," Marchesin told Fox Sports.
Lanus were happy with the away result while ruing striker Santiago Silva's miss in the first half with an open goal at his mercy.
The second leg of the final of South America's equivalent to the Europa League will be played at the "Fortress" in the Buenos Aires suburb of Lanus next Wednesday.
Lanus, who beat Argentine big guns River Plate and Libertad of Paraguay on their way to the final, are also vying for their second league title with the final round of matches concluding on December 15.
Ponte Preta, a modest side relegated from the Brazilian championship's Serie A last month, eliminated holders Sao Paulo in the semi-finals.