Manchester City player Aleksandar Kolarov is reportedly at the centre of an alleged racism complaint.
Aleksandar Kolarov produced a moment of captain's inspiration, curling home a superb free kick as Serbia got their World Cup Group E campaign up and running with a 1-0 victory over Costa Rica on Sunday.
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.
Here is a round-up of results from the European League matches played on Friday.
Premier League champions in 2012 and 2014, Manchester City went to the top of the table with a 3-1 victory over West Ham United on Sunday. They moved on goal difference above Chelsea and neighbours Manchester United, who have also won their three opening games.
Chelsea brushed Norwich City aside 4-1 at Stamford Bridge on Saturday to open up a four-point lead at the top of the Premier League after Everton, who were second, drew 2-2 at Wigan Athletic and slipped to third.
Big-spending Manchester City opened the Premier League title door to Manchester United ahead of the Old Trafford's team visit to Blackburn Rovers on Monday after being held to a 3-3 home draw by Sunderland.
Skipper Robin van Persie scored a hat-trick as Arsenal beat Chelsea 5-3 in a remarkable Premier League match at Stamford Bridge but Manchester City stayed top of the Premier League with a 3-1 home win over Wolverhampton Wanderers on Saturday.
Carlo Ancelotti's side held a two-goal lead at halftime thanks to strikes from Dries Mertens and Kostas Manolas, but Balotelli pulled one back as Brescia rallied after the break.
Manchester City gave renewed hope to the chasing pack in the battle for a Champions League spot as they were held to a battling 1-1 draw at relegation strugglers Newcastle United on Tuesday.
Newly-acquired Spain forward Pedro highlighted his potential worth to Premier League champions Chelsea with a goal, assist and eye-catching performance in their 3-2 win at West Bromwich Albion on Sunday.
News of all that's transpired on and off the football field
Liverpool, inspired by two-goal Egyptian Mohamed Salah, took a big step towards the Champions League final with a 5-2 win over AS Roma in their semi-final, first leg at Anfield on Tuesday.
Manchester City's impressive 2-0 victory at Everton on Sunday equalled a club record of nine successive Premier League wins.
Goals from Victor Moses and Daniel Sturridge eased Liverpool through a tricky FA Cup fourth round tie at Championship (second division) Bournemouth on Saturday although they had to work hard for a 2-0 victory.
Real Madrid produced a gutsy performance to earn a 1-0 win at Sevilla, on Sunday, which took them level on points at the top of La Liga
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'We always knew it was going to be an important one playing against a quality side, but I think it affected us a little bit too much.
Serbia and Costa Rica begin their World Cup campaigns on Sunday with the teams likely to adopt contrasting approaches to making the most of their limited resources at the tournament.
Liverpool finished 2016 second in the Premier League with a 1-0 victory over third-placed Manchester City on Saturday.
Manchester City went top of the Premier League after securing a controversial 2-0 win at Newcastle United on Sunday with an early Edin Dzeko goal and a stoppage time effort from Alvaro Negredo.
'We saw Messi play like a kid in the school playground today'
Serie A leaders Juventus scored twice in the last five minutes to win 3-2 at Inter Milan, who had earlier come from behind to lead despite playing with 10 men in an extraordinary match on Saturday.
Jamie Vardy became the first player to score in 11 consecutive Premier League matches when he gave Leicester City the lead in a 1-1 draw with Manchester United at the King Power Stadium on Saturday.
Arsenal's victory was scrappy and nervy but Laurent Koscielny's 72nd-minute winner was enough to move them two points clear at the summit after LeicesterCity's surprise push faltered with a goalless draw at home to 10-man Bournemouth.
Two brilliant strikes from Isco and a late goal from Alvaro Morata gave Spain a spectacular 3-0 win over Italy, their nearest challengers in Group G, to move into the driving seat for automatic qualification to the 2018 World Cup.
The 20-year-old was jeered at the Melbourne Cricket Ground when he tripped over the ball on one of his first touches in the area, but a minute later soaked up the acclaim after slotting home a through ball from Nigerian teenager Kelechi Iheanacho.
Brazil need solutions after coming unstuck against Swiss
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field.
Cristiano Ronaldo was involved in all three of his team's goals as Juventus came from behind to beat Napoli 3-1 in a Serie A top-of-the-table clash on Saturday to maintain their perfect start to the season.
Three matches into the Premier League season following a stunning title success by 5,000-1 outsiders LeicesterCity, the table already has a more familiar look.
Paris St Germain extended their Ligue 1 lead to 13 points with a 4-3 home victory against Girondins de Bordeaux on Sunday but the French champions were again exposed at the back and had Neymar sent off. A Marquinhos double, Edinson Cavani's 200th PSG goal and a goal by Kylian Mbappe put the capital side on 65 points from 26 games but they lost captain Thiago Silva to a muscle injury and Neymar picked up a straight red card for a late challenge in stoppage time.
Frank Lampard, Chelsea's all-time leading scorer, netted against his old club when he came on as a late substitute for Manchester City to give the champions a 1-1 draw.
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Chelsea's on-loan Brazilian international Alexandre Pato scored on his debut to help push pathetic Aston Villa to the verge of inevitable relegation with a seventh successive Premier League defeat on Saturday. Pato, the former Milan starlet who has been kicking his heels since joining from Corinthians two months ago, came on as a 25th-minute substitute and was immediately involved in the move which led to Ruben Loftus-Cheek netting his first league goal.
AS Roma pulled off one of the great Champions League comebacks by knocking Barcelona out with a remarkable 3-0 win in their quarter-final second leg on Tuesday, overcoming a 4-1 deficit from the first game to reach the last four on away goals.
Ronaldo's replacement Dybala scored in the 77th minute with a goal the Portuguese would have been proud of. After a quick exchange of passes, the Argentine twisted past Alessio Romagnoli and beat Gianluigi Donnarumma with a right foot shot.
Emotions ran high as Nantes paid tribute to their former player Emiliano Sala on Wednesday in their first game since the Argentine went missing in a light aircraft over the English Channel.
Manchester City were never out of the title race and the Premier League champions did not need to change their style despite a frustrating to start the season, manager Manuel Pellegrini has said.