German forward Miroslav Klose was also on target as Lazio, enjoying a superb start under new coach Vladimir Petkovic, won their first three matches of the league season for the first time since 1974.
Napoli and titleholders Juventus also have a maximum nine points after both enjoyed 3-1 wins over Parma and Genoa while Sampdoria have a 100 percent record but have only eight points after having one deducted over the Calcioscommesse match-fixing scandal.
AS Roma, who produced a masterclass of attacking football as they won 3-1 at Inter Milan in their last game, squandered a 2-0 lead and lost 3-2 at home to Bologna while Udinese also blew a 2-0 goal advantage in a 2-2 draw at Siena.
Diego Milito and Antonio Cassano scored in each half to give Inter a 2-0 win at promoted Torino in the evening game, leaving the visitors with six points from three games.
Hernanes put Lazio ahead with a superb solo effort in the fifth minute, evading two tackles before firing in a long-range left-foot shot which went in off the post.
The Brazilian midfielder, overlooked by national team coach Mano Menezes since February, also set up the second goal when he again left his marker for dead.
Although he was foiled by Chievo goalkeeper Stefano Sorrentino, Germany forward Klose was on hand to score from the rebound in the 38th minute for his third goal of the season.
Hernanes produced another inspirational moment for the third goal as he burst down the left to the byline, then managed to squeeze the ball past the bemused Sorrentino from a narrow angle in the 74th minute.
Sergio Pellissier pulled one back for the hosts with an 83rd-minute penalty.
Argentine forward Maxi Lopez scored twice and Paraguay midfielder Marcelo Estigarribia was also on target as Sampdoria won 3-2 at promoted Pescara, who have lost all three games.
Juventus, unbeaten in the league since losing to Parma in their penultimate game of the 2010/11 season, came from behind to win at Genoa, extending their run to 42 matches.
Ciro Immobile gave the hosts a deserved 18th minute lead, scoring with a low shot from the edge of the penalty area despite being surrounded by four Juventus defenders.
Juventus were on the back foot for much of the first hour, their players complaining every refereeing decision, and it took an excellent performance by goalkeeper Gianluigi Buffon to keep them in the game.
The match changed completely after Emanuele Giaccherini side-footed the equaliser in the 61st minute.
Substitute Mirko Vucinic converted a 78th minute penalty after a foul on Kwadwo Asamoah who scored the third himself six minutes later, sliding the ball into an empty net after Vucinic's cross was deflected into his path.
Edinson Cavani sent Napoli on their way with a second minute penalty and Goran Pandev added the second in the 39th minute, before Marco Parolo pulled one back just before the break.
Lorenzo Insigne made the game saf
