Paris St Germain and Istanbul Basaksehir players took a knee before the game in reaction to a racist comment by a match official that caused the Champions League match to be rescheduled.
Neymar scored a stunning hat-trick as Paris Saint-Germain romped to a 5-1 win over Istanbul Basaksehir when their Champions League match resumed a day after being suspended in an unprecedented walkout over a racism row.
Kylian Mbappe also scored twice for the French side, who secured top spot in their Champions League group and with it a potentially easier draw in the last 16.
Players from Paris Saint-Germain and Istanbul Basaksehir took a knee on Wednesday before restarting their Champions League match suspended 24 hours earlier when the teams walked off the pitch in an unprecedented protest at the racist comment by a match official.
The teams gathered around the centre circle and were joined by the match officials as they kneeled in support of the Black Lives Matter movement.
Before that they sported t-shirts with the slogan "No To Racism" while warming up at the Parc des Princes, where large banners in the empty stands carried the same message.
Banners read 'Support to Mr Webo... Proud of the players... Against racism,' and 'Paris united against racism.'
UEFA had two banners of their own with both clubs' logos, reading 'No to racism,' one in French and the other in English.
Taking a knee was popularised by San Francisco 49ers quarterback Colin Kaepernick in 2016 and gained steam as an anti-racism protest following the death of George Floyd, a Black man who died in police custody in Minneapolis in May.
The game restarted where it stopped on Tuesday, in the 14th minute, when a touchline argument erupted over accusations the Romanian fourth official, Sebastian Coltescu, had described Basaksehir's Cameroonian assistant coach Pierre Webo as "black," or "negru" in Romanian.
Coltescu and the other Romanian match officials were replaced for the restart by a new refereeing team headed by the Netherlands' Danny Makkelie.
Already qualified for the last 16 thanks to Manchester United's defeat to RB Leipzig in Germany on Tuesday, PSG still needed to win the restarted game to secure top spot in their group and raced into a 3-0 lead by half-time with Neymar scoring twice and Kylian Mbappe scoring a penalty.
Mbappe had played a prominent role in Tuesday's heated discussion on the touchline, tweeting "Say no to racism."
Turkey's President Recep Tayyip Erdogan, tweeted that he "strongly condemns the racist remarks," while France's sports minister Roxana Maracineanu, who was born in Romania, praised the players' "historic decision."
Basaksehir midfielder Giuliano said the official's comment was "disgraceful."
"[The comment] was very clear, many people heard, including our coach. It was disgraceful," he told Brazilian media.
"As a team and a group, we decided to protest because that is unacceptable. Racism has to end."
The row flared after Webo was shown a red card.
Television microphones in the empty stadium – matches are taking place without spectators because of Covid-19 restrictions – picked up a furious Webo repeatedly asking why a racist term had been used to describe him.
'No to racism'
European football's governing body UEFA promised a "thorough investigation" and suspended the red card shown to Webo while it probes the matter.
The French government's spokesman Gabriel Attal condemned all racism in sport and commended the "solidarity" shown by both teams.
Rio Ferdinand, the former Manchester United and England defender and now a TV pundit, said on BT Sport in the UK: "I think we are at a disturbing tipping point. Not a week goes by without an incident involving race.
"The players walking off is a step in the right direction, but it can't just be left to them."
Ferdinand's brother Anton was involved in a high-profile incident in 2012 when Chelsea player John Terry was accused of racially abusing him during a match in England.
Many athletes have taken a strong stand against racism since Black Lives Matter protests flared around the world over the death of Floyd during his arrest in Minneapolis in May.
The Turkish champions had refused to restart the game on Tuesday as long as fourth official Coltescu was still involved.
"The fourth official used the word 'negro' in front of everybody," Basaksehir president Goksel Gumusdag told Turkish television channel TRT Spor.
Basaksehir responded to the incidents by tweeting "NO TO RACISM #Respect", along with a photo of UEFA's anti-racism logo.
The message was retweeted by PSG.
"All forms of racism go against the values held by Paris Saint-Germain, the club's chairman, staff and players," the French champions said.