Inter Milan routed visiting Bologna 4-1 in the Serie A on Saturday and continued its winning run since Leonardo took over as coach.
Leonardo replaced Rafa Benitez on Christmas Eve and Inter has since won all four of its games to move to eight points behind league leader AC Milan, which was playing Lecce on Sunday.
''We know what we are doing now and how we want to play,'' Leonardo said. ''We are winning difficult games that we were losing before. We played well tonight and deserved to win.''
Dejan Stankovic and Diego Milito started the scoring in the first half and Samuel Eto'o's brace in the second confirmed Inter's dominance.
Substitute Henry Jiminez scored a late consolation for Bologna in the 77th.
Inter captain Javier Zanetti played his 519th game for the club, equaling the record held by 1982 World Cup-winner Giuseppe Bergomi.
Also, an uninspired Napoli failed to close to within a point of Milan when it was held to 0-0 at home by Fiorentina.
Inter made a strong start and both Milito and Maicon went close with early chances.
Stankovic opened the lead in the 20th. Eto'o found him in space in the area and the Serb had the straightforward task of sidefooting the ball past Viviano.
Milito then linked up with Zanetti for the second. Zanetti played his fellow Argentine in behind the Bologna defense and Milito held off Miguel Britos to fire into the top of net.
Bologna captain Marco Di Vaio came close twice before the break, but on each occasion Inter goalkeeper Luca Castelazzi was equal to his efforts.
Eto'o linked up with Milito in the 63rd to score his 22nd Inter goal of the season. He cut in from the left wing, slipped the ball to Milito, who backheeled it back to the Cameroonian who curled the ball inside the far post.
Nine minutes later he scored his 23rd by curling a free kick past Viviano.
Jiminez then scored when he was first to a loose ball in the area.
''It was a match that we had to win regardless of what I was celebrating and this is what we did,'' Zanetti said.
''We have been able to welcome back a number of injured players and we now have to maintain this form till the end of the championship.''
Napoli, meanwhile, began at a high tempo, but despite dominating Fiorentina early on, was unable to create any clear chances.
Paolo Cannavaro had the best chance for the hosts in the first half. Ezequiel Lavezzi crossed from the right, Edinson Cavani flicked on, but Cannavaro was unable to shoot before Fiorentina goalkeeper Artur Boruc smothered the ball.
Adem Ljajic then fired over the bar from the penalty spot in the 39th after Mario Santana picked him out in a crowded penalty area.
After the break neither side managed to find any fluency, though Napoli attempted to increase the pace of the game as time ran out and Dumitru came close with a scrambled effort in stoppage time.
''I'm happy with how we played,'' Fiorentina coach Sinisa Mihajlovic said. ''We had a good game and created scoring chances. We tried to win, but just couldn't finish.''