ROME, Jan 18 (Reuters) - Juventus had their lead at the top of Serie A trimmed to eight points when they were held to a 1-1 draw at Chievo Verona on Wednesday.The result at Chievo's Bentegodi stadium left Juventus with 53 points from 20 matches. Second-placed Inter Milan kept their title challenge on course with a 1-0 victory over bottom-placed side Treviso. AC Milan lie third on 43 points after a Filippo Inzaghi goal gave them a 1-0 win against Ascoli. Fiorentina remain fourth on 40 points despite a 3-1 defeat at the hands of Sampdoria. Chievo had lost every game against Juventus at the Bentegodi since they arrived in the top flight in 2001 and did not look capable of much resistance in the early stages as keeper Alberto Fontana twice parried shots by Zlatan Ibrahimovic. It seemed only a matter of time before Juve took the lead, but in the 22nd minute a Chievo break ended with midfielder Franco Semioli racing down the left to cross for Daniele Franceschini to volley past Gianluigi Buffon. Their lead was short-lived. Midfielder Patrick Vieira headed Juve's equaliser just past the half hour but the champions never managed to stamp their authority on the match. Both teams created chances in the second half. Chievo defender Federico Giunti hit a long-range effort just over the bar while at the other end Fontana dived to scoop Alessandro Del Piero's low cross away from the feet of David Trezeguet. RARE SLIP The draw was only the third time this season the leaders had dropped points in Serie A, following a 3-1 defeat to Milan in October and a 1-1 draw with Lazio in December. The main beneficiaries of Juve's slip were their nearest challengers Inter, who went ahead in the 22nd minute at Treviso courtesy of a Julio Cruz header. Adriano went close to extending their lead with a shot that hit the post just before the break. Treviso occasionally made life uncomfortable for the visitors. Andre Pinga curled a free kick against the bar and Marco Borriello was unlucky not to earn a penalty after he was flattened by Inter defender Ivan Cordoba. Milan's players also laboured for their three points, though after four defeats in their last five away matches they were probably glad to be back in the familiar surroundings of the San Siro stadium. Inzaghi's goal came on the break. The striker sprinted half the length of the pitch through Ascoli's back-pedalling defence before slotting the ball past Ferdinando Coppola at his near post. Serie A top scorer Luca Toni's 19th goal in 20 games was not enough to save Fiorentina from a heavy defeat by Sampdoria in Genoa. Fifth-placed Livorno drew 0-0 at Lecce, while AS Roma racked up their fourth win in a row, a 3-1 victory over Reggina with two goals by Francesco Totti, to maintain their bid for a European berth in sixth.