Napoli striker Lorenzo Ancini scored a penalty in the second half to cancel Juan Pernat's 1-0 draw with Barry Sesan German to make it all the way in Group C of the Champions League.
St Germain took the lead in the first half and Kellian Mbabie moved the ball to Bernat to score from close range after escaping the control before halftime.
Lensini equalized from the penalty spot in the 63rd minute after Jose Cajun took advantage of defender Tiago Silva's mistake.
Liverpool and Napoli have six points from four games, five points for San Germain and four points for Red Star Belgrade.
