Chelsea coach Claudio Ranieri said his team’s positive approach held the secret to their spectacular 4-0 Champions League away win over Lazio in Group G on Tuesday. "Lazio started very strong, but we tried to play our game, pass the ball and score goals," he told reporters, "I said yesterday that Chelsea must play with a winning mentality. Perhaps Lazio were nervous because after drawing at home with Sparta Prague and losing to us at Stamford Bridge they were under a lot of pressure." Group leaders Chelsea played the better football in a tightly contested first half at Rome’s Olympic stadium and took the lead in the 14th minute when Lazio keeper Matteo Sereni spilled a Juan Sebastian Veron free kick into the path of Hernan Crespo, who forced the ball over the line. But the balance of the match swung decisively early in the second half when Lazio defender Sinisa Mihajlovic was sent off for a second booking. Lazio crumbled as goals by striker Eidur Gudjohnsen and midfielders Damien Duff and Frank Lampard completed Chelsea’s perfect night. Ranieri, however, insisted: "Lazio didn’t play so badly, they created chances and had shots on goal, which (goalkeeper Carlo) Cudicini did very well to save. "The red card maybe changed things. From that point on it became more and more difficult for them to get back ino the match. They started to make trivial mistakes, messing up passes that normally they would make easily. They seemed nervous, but we were lucky to take our chances so well." While the result gave Chelsea nine points, it left Lazio at the bottom of Group G, equal on four points with Sparta Prague but two behind Besiktas.