The draw lifted Parma into a fourth-place tie with Inter Milan, both with 31 points, ahead of Sunday's matches of the 17th round. Udinese moved to 26.
At Modena, the draw left both teams disappointed.
Lazio, coming off straight losses, needed a victory to stay closer to the Champions League spots, the top four places in the Serie A.
Modena, struggling in the lower half of the standings, also needed the full stake to stay away from the relegation zone.
Lopez, the quick Argentine forward, put Lazio in front after 24 minutes at Modena Alberto Braglia stadium.
Starting the action from Lazio's midfield, Lopez led a fast counter attack in a team with Roberto Muzzi catching Modena defense wide open. After receiving the final pass from the Italian teammate, unmarked Lopez beat veteran goalkeeper Marco Ballotta from 7m with a precise left-footed shot.
Campedelli made it 1-1 in the 61st, scoring in a melee.
French league
Monaco stumbled to a 0-0 tie at Bastia Saturday, but remained seven points clear at the top of the French first division as Paris Saint-Germain failed to take advantage.
Monaco has 46 points, while second place PSG, which was held 0-0 at home by lowly Metz, has 39 points.
Lyon closed the gap on the top two, beating struggling Montpellier 3-0 at home to move onto 38 points. Vikash Dhorasoo, Peguy Luyindula and substitute Julien Viale all scored for the defending champion.
Fourth place Auxerre, which enjoyed a 2-0 win at Strasbourg courtesy of Olivier Kapo and Djibril Cisse, has the same total as Lyon but remains in fourth place with an inferior goals difference.
France international Cisse leads the scoring charts with 15 strikes so far this term.
Meanwhile, Sochaux suffered a heavy 4-0 defeat at Rennes and stays in fifth spot on 35 points. Swiss international Alexander Frei notched twice for Rennes.
Bordeaux, which is resurgent following a poor start to the season, crept into sixth place after a 2-0 home triumph over relegation-threatened Guingamp -- with goals from young midfield prospect Pablo Francia and Sylvain Franco.
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