Crystal Palace winger Wilfried Zaha called out racial abuse on Twitter as three English Football League clubs reported alleged racist incidents on Saturday.
Zaha was brought down by Newcastle United's DeAndre Yedlin for Luka Milivojevic's decisive penalty in a 1-0 Premier League win.
After the match, Zaha shared a subsequently deleted tweet calling him a "diving monkey".
On the same day, lower league clubs made headlines due to other incidents.
Derby manager Frank Lampard said midfielder Duane Holmes was abused in the dugout following his 74th-minute substitution.
"Duane Holmes complained that he was racially abused - I didn't see it, I was facing play and a fan came up to him at the side of the dugout and abused him," Lampard told Sky Sports.
"Because it's such an important issue I don't want to go beyond what I know, but it was very clearly reported by the players and the people around."
Your support at Griffin Park this afternoon was incredible.— Derby County (@dcfcofficial) April 6, 2019
We'll see you again at Ewood Park on Tuesday. pic.twitter.com/JwkF6lGsTC
A statement from Brentford read: "Brentford FC will continue to liaise with the Metropolitan Police, who will now investigate the incident.
"The club utterly condemns discrimination of any kind. It is abhorrent and has no place in society and we are determined to drive it out of Griffin Park."
Wigan Athletic have reported an abusive message sent to their defender Nathan Byrne to the police.
A statement issued following their 2-2 draw against Bristol City read: "Wigan Athletic Football Club are angered by racist abuse received on the personal Twitter account of one of our players, Nathan Byrne, on Saturday afternoon.
"We have reported the incident to the police and will work with the relevant authorities to assist them with their investigations.
"There is no place for discrimination in society and social media is not an exception to those rules. We find this behaviour abhorrent."
Northampton Town said their players were subjected to "appalling" behaviour and called for anyone with information to come forward after their on-loan Derby County midfielder Timi Elsnik claimed his team-mates were racially abused outside their hotel ahead of Saturday's League Two fixture at Notts County.
"Went for a pre-match walk with the team in Nottingham and this young man outside the hotel started racially abusing some of our lads," Elsnik's tweet read.
"The most disgusting thing I've seen and heard! He's done it in front of his girl as well with no shame so he must do it all the time. Absolute idiot!"
The incidents come after a week when England international Danny Rose said he "can't wait to see the back of football" and expressed frustration over a lack of action taken against racism from football fans, while Juventus forward Moise Kean celebrated a goal against Cagliari by holding his arms outstretched in front of the opposition fans – seemingly in response to alleged racial chanting from the stands.
"Another week, another group of players racially abused," said anti-discrimination charity Kick It Out. "We won't stop highlighting this disgraceful behaviour while it remains deeply ingrained within football.
"We'll be liaising with the relevant authorities and offering support to clubs and players involved."