AC Milan won their 17th Italian title as they lifted the Serie A crown for the first time since 1999 with a 1-0 win over second-placed AS Roma.
Ibrahimovic and Lukaku, who played together at Manchester United, exchanged words at the end of the first half before the pair had to be restrained as the players left the pitch for the interval.
AC Milan coach Leonardo and Juventus counterpart Alberto Zaccheroni bid farewell in contrasting fashions on Saturday when the Brazilian's side eased to a 3-0 win in their final league game of the season.
AC Milan produced a storming comeback with goals by Maxi Lopez and Stephan El Shaarawy to win 2-1 at title rivals Udinese on Saturday and move top of Serie A as their strikers made light of Zlatan Ibrahimovic's absence.
Barcelona need to avoid over-exuberance if they are to overturn a 2-0 deficit in Tuesday's Champions League clash at home to AC Milan, midfielder Cesc Fabregas said on Thursday.
David Beckham made his AC Milan debut with a steady first-half run-out against Hamburg SV in a friendly on Tuesday won 4-3 on penalties by the Italians after the match finished 1-1. Beckham, 33, has joined the Serie A club on a short loan spell from Los Angeles Galaxy to keep up his fitness and stay in contention for the England team during the US close season.
AC Milan shrugged off an unbelievable Robinho miss, and an interruption caused when teargas was thrown outside the ground, to record a 2-0 win at Genoa that took them to the top of Serie A on Friday.
Real Madrid fought back from two goals down as Vinicius Jr grabbed a hat-trick in a thrilling 5-2 win over visitors Borussia Dortmund in the Champions League.
He was criticised following last week's 3-2 first-leg defeat to United at Old Trafford.
The 33-year-old midfielder has no experience of Italian football and it is not easy to see how he would fit into AC Milan's plans with famous Brazilians Kaka and Ronaldinho already with the Rossoneri.
Schalke 04 have signed Dutch striker Klaas-Jan Huntelaar from Italian side AC Milan, coach Felix Magath said on Tuesday.
Francesco Valiani scored a stunning goal as promoted Bologna beat AC Milan 2-1 at the San Siro on Sunday to spoil Ronaldinho's Serie A debut.
AC Milan have been left dwelling on the past as they prepare to host Barcelona in a Champions League last-16 first leg tie on Wednesday when Lionel Messi will try to score for the Catalans for the 15th match in a row.
AC Milan forward Antonio Cassano is set to join Inter, with Giampaolo Pazzini moving in the opposite direction, the two clubs said on Tuesday.
The Brazilian said he was being humiliated at Italian club AC Milan, where he was left on the substitutes' bench.
Barcelona pulled off a remarkable Champions League comeback when Lionel Messi scored twice in a thrilling 4-0 victory at home to AC Milan on Tuesday that sent the Spanish club through to the last eight 4-2 on aggregate.
Antonio Cassano scored his first AC Milan goal and Robinho struck twice to help the Serie A leaders end a run of two straight draws in a 4-0 home thrashing of Parma on Saturday.
Serie A leaders AC Milan slipped up for the second straight game in a 1-1 draw at Genoa on Sunday which opened the door for Napoli to cut the gap at the top to three points.
AC Milan went a point clear in Serie A on Saturday after Antonio Nocerino and a Zlatan Ibrahimovic penalty gave the champions a hard-earned 2-0 win over lowly Siena at the San Siro.
Wayne Rooney scored twice again as Manchester United cruised into the quarter-finals of the Champions League after a 4-0 win over a feeble AC Milan sent them through 7-2 on aggregate on Wednesday.
The two players, who are injured, will miss Manchester United's Champions League clash against AC Milan.
La Liga leaders Real Madrid were held to a frustrating 1-1 draw at lowly city rivals Rayo Vallecano on Sunday as Joselu's early strike was cancelled out by Raul de Tomas' penalty, a result that could spice up the title race with surprise package Girona.
Short-term loan signing David Beckham is in excellent shape and could make his Serie A debut in AC Milan's first league match after the winter break at AS Roma next week, coach Carlo Ancelotti said on Saturday.
Jose Mourinho's quest for a unique Champions League hat-trick began in style with Real Madrid on Wednesday, the nine-time winners beating Ajax Amsterdam 2-0 on a night of commanding wins for the main contenders.
Robinho arrested in Brazil to serve rape sentence
Soccer player Alexandre Pato and actress Sthefany Brito smile after their wedding at Sao Francisco de Paulo church in Rio de Janeiro on Tuesday.
Thiago Silva powered home a header in the second minute of stoppage time to steal a 2-2 draw for AC Milan at holders Barcelona in the heavyweight pair's Champions League Group H opener on Tuesday.
Unbeaten Juventus snatched a late goal to draw 1-1 at AC Milan in Serie A's top of the table clash on Saturday after the hosts had a goal disallowed when officials failed to spot the ball had crossed the line.
AC Milan and Arsenal hope to rediscover their best form for Tuesday's Champions League last-16 second leg after both sides showed signs of weariness. The first leg in London two weeks ago finished 0-0, one of a number of fitful draws the pair have managed lately.
David Villa scored his first goal for Barcelona in a friendly against AC Milan on Wednesday, while behind the scenes the two clubs prepared to continue their negotiations over Barca striker Zlatan Ibrahimovic.
Lionel Messi has set the bar so high for himself that when he does not score for a few games it prompts an outburst of speculation and head-scratching about what might be ailing the Argentine World Player of the Year.
IMAGES from soccer matches played across Europe on Sunday.
AC Milan and Liverpool won their Champions League qualifying rounds.
News of all that's transpired on and off the football field
AC Milan beat visitors Lazio 2-0 to claim consecutive Serie A wins for the first time since February thanks to Carlos Bacca's fifth goal of the season and an M'Baye Niang penalty on Tuesday.
Barcelona expect AC Milan to go all out for victory at the Nou Camp on Wednesday
Juventus continued their charge towards a fourth successive Serie A title as they predictably swept aside AC Milan 3-1 on Saturday to complete a league double over their old rivals.