French champions PSG, unbeaten at the Parc des Princes in all competitions since November 2012, have 44 points from 19 matches while Lille stayed third four points off the pace, one behind second-placed Monaco.
Laurent Blanc's side looked on the way to a routine win after Zlatan Ibrahimovic scored his 18th league goal of the season but Rio Mavuba and Salomon Kalou gave the visitors a 2-1 lead before Basa beat his own keeper with less than 20 minutes left.
PSG were without Edinson Cavani who earlier this week went back to Uruguay to deal with a personal matter, while Lille defender Simon Kjaer was ruled out in the last minute because of a buttock muscle pain.
The home side took control of the match and came close in the 22nd minute when Vincent Enyeama spectacularly parried away Ezequiel Lavezzi's half volley after the Argentine had been set up by fullback Lucas Digne, who deputised for the injured Maxwell on the left flank.
Thiago Silva skied Ibrahimovic's cross over the bar from point-blank range in the 33rd minute as PSG upped the pace.
There was nothing Enyeama could do in the 36th minute when Ibrahimovic unleashed a cannonball 25-metre free kick that went into the top corner after taking a slight deflection off a Lille defender.
One minute before halftime, Mavuba fired past Salvatore Sirigu after collecting Salomon Kalou's cross from the right, shortly after he and Ibrahimovic had received a yellow card for a brief scuffle on the pitch.
Lille took the lead eight minutes into the second half when Kalou beat Sirigu from the spot after Digne had brought down Franck Beria in the box.
With a first home defeat this season looming, Blanc substituted centre back Alex with attacking midfielder Javier Pastore, who has had more downs than ups since he joined from Palermo in 2011 for a 42 million euro fee.
It was Basa, however, who did the job for PSG when he deflected a corner kick into his own net in the 72nd minute.