The Brazilian winger, who earned his side a 1-0 win at neighbours Saint-Etienne last weekend, fired home from just outside the box with six minutes to go to cancel out Jordan Loties' opener.
Lyon stay top on 35 points from 17 games, three ahead of Paris Saint-Germain after the capital side hammered Valenciennes 4-0 away on Tuesday. The two sides will clash at Parc des Princes on Sunday.
Olympique Marseille are third, level on points with PSG but behind on goal difference, after they won 2-1 at Bastia.
Lyon, who were missing suspended Maxime Gonalons and the injured Clement Grenier and Yoann Gourcuff in the midfield, struggled to create clear-cut chances and mainly relied on long-range efforts in the first half.
France striker Bafetimbi Gomis, whose recent run of scoring form lifted Lyon to top spot, failed to convert a pass from Bastos six minutes before the break.
Lisandro Lopez came off the bench after the interval but the Argentine striker, returning from four weeks out injured, could not boost his side.
Lyon eventually conceded in the 74th minute when goalkeeper Remy Vercoutre parried Salif Sane's header only to see the ball rebound off Loties' stomach and roll into the net.
Bastos quickly levelled with his fifth goal in eight appearances.
"We left a lot of energy in the derby [at Saint-Etienne] and our minds were already turned to Paris," coach Remi Garde told reporters before criticising the referee after they were denied a penalty early in the second half.
"I think it's the turning point in the game because we have never lost after taking the lead at home," he said.
"I admit my team did not play at their usual level but we were not the only ones to be poor tonight."
Nancy moved up to 19th after a fifth draw in a row.
In Bastia, where the game was played behind closed doors, Mathieu Valbuena deservedly put Marseille ahead with a superb volley from just inside the box in the 15th minute.
Andre Ayew doubled the lead from the penalty spot on 70 minutes after goalkeeper Landry Bonnefoi had fouled his younger brother Jordan.
Anthony Modeste scored a late goal but Bastia did not go on to worry the visitors, who clinched their sixth away league win and also welcomed back striker Andre-Pierre Gignac six weeks after he suffered a broken foot.
Alain Traore netted a spectacular strike a minute before the break to inspire Lorient to a 2-0 home victory over Sochaux, their third consecutive league win.
Lamine Kone took advantage of confusion into the box following a corner to score a second goal eight minutes into the second half for Lorient, who climbed up to fourth on 27 points.
Champions Montpellier moved up to 11th after they recovered from conceding an early goal to win 2-1 at Stade Brest.
