Everton versus Liverpool is a fixture that's featured a lot of controversial moments down the years.
Since the turn of the millenium, there's been Jack Rodwell's red card for a 'foul' on Luis Suarez, Jordan Pickford's knee-high tackle on Virgil van Dijk that wasn't punished and the infamous 'Mark Clattenburg derby' from 2007.
But perhaps the most controversial incident from a Merseyside derby in the 21st century came as far back as 2000.
In a Premier League match between the two sides at Goodison Park, Everton had a goal disallowed in the final minute of stoppage-time.
Sander Westerveld's kick from inside his own penalty area hit Don Hutchinson's back and the ball looped over the Liverpool goalkeeper and into the back of the net.
But referee Graham Poll had already blown for full-time before the ball crossed the line, meaning that the goal did not stand.
Needless to say, the Everton players were absolutely fuming and surrounded Poll demanding answers.
Check out footage of arguably the craziest disallowed goal in Premier League history here...
Video: Everton's controversial disallowed goal vs Liverpool in 2000
That's just absolute madness, isn't it? Thankfully, we haven't seen those farcical events on Merseyside repeated in the decades since and hopefully it stays that way.
In the immediate aftermath of the game, Poll was in no mood to admit that he'd made a horrendous and costly error.
"I looked at my watch and saw that it was the last kick of the game," he said. "We had had the correct amount of time for stoppages so I blew. I blew for time as he kicked the ball but some of the Everton players got excited as happens in derby games. But I was very clear in my own mind."
But many years later, the referee who infamously booked Josip Šimunić three times in one World Cup match came clean and recognised that it was a huge mistake on his part.
Poll wrote in his Daily Mail column in 2010: "I jogged back to the centre circle, checked my watch which showed that time had elapsed and blew my whistle as I thought Westerveld had booted the ball upfield.
"Unfortunately, he had kicked it into Don Hutchinson and the ball was on its way into the Liverpool goal. I stood firm and the 'goal' did not count.
Who is the BIGGEST Premier League flop of the season? Lukaku, Grealish or Sancho? (Football Terrace)
"I was wrong back in April 2000 and have to apologise to any Everton fans that I meet even now – they never forget! I never repeated the act of blowing at an inappropriate time."