Leonardo has already forgotten AC Milan's 4-0 defeat at Manchester United in the Champions League and is focused on challenging for the title.
The Rossoneri failed to overturn a 3-2 defeat at home with a heavy loss in England on Wednesday night.
Ahead of Sunday's home game against Chievo, Leonardo said: "I had imagined a different game at Old Trafford.
"We had structural problems but we also have to recognise the strength of our rivals.
"I nevertheless believe that one should not judge Milan based on the game at Old Trafford.
"We are still second in Serie A, four points behind Inter.
"Let's focus on our strengths and not be conditioned by the negative result at Manchester United.
"This Milan side does not need to be transformed, it just needs to be intelligent and make sure this setback does not have a negative effect on our aims this season."
Inter Milan are still alive in Europe and will take on Chelsea in London next week after winning the first leg at the San Siro.
Once again, Inter coach Jose Mourinho will have to watch his side's match at Catania on Friday from the stands while he completes a touchline ban.
Inter's players believe his absence in recent games has hindered their performances.
The Nerazzurri have drawn four of their last five games.
"If the team plays well and with the right attitude, there is no need to have the coach on the bench to win," Mourinho said.
"I am not the one that is playing. I don't score. I don't make the saves."
Roma are in third place, two points behind AC Milan ahead of Sunday's match at Livorno.
Claudio Ranieri's team were fortunate to claim a point at home to Milan in the last round.
In-form Palermo visit Udinese riding a three-game winning streak that has lifted Delio Rossi's side into fourth place - the last Champions League qualifying spot.
Juventus, who trail Palermo by two points, host bottom side Siena this weekend.
Sampdoria are in sixth place after last week's 2-1 win over Lazio. The Genoa outfit play at Bologna on Sunday.
Fiorentina won 3-2 but were knocked out of the Champions League by Bayern Munich on Tuesday in Florence.
The Viola will try to take the positives from that performance for Saturday's game at Napoli.
Cesare Prandelli's side lie 10th in Serie A having won just one of their last nine league games.
Cagliari are looking to improve their form away from home when they meet Genoa at the Stadio Luigi Ferraris on Sunday.
The Sardinian club have taken just one point in their last four road games.
A win on Sunday against relegation-threatened Atalanta would see Parma take a giant step towards securing their Serie A status.
Francesco Guidolin's side have an 11-point cushion over the drop zone with 11 games remaining.
Lazio go into Sunday's match against Bari under immense pressure.
The Biancoceleste have won just one of their past nine encounters and last weekend's 2-1loss at Sampdoria left Edy Reja's side 17th in the standings, only three points above the relegation zone.
