Arsenal legend Patrick Vieira has revealed he started the infamous tunnel row between the Gunners and Manchester United in 2005.
Vieira sparked a hostile exchange between the two bitter rivals at Highbury as the players lined up in the tunnel ahead of kick-off.
The bust-up was partially captured by television cameras, with United's Roy Keane responding angrily after Vieira exchanged words with Gary Neville.
United went on to win the Premier League clash 4-2, with neither side punished for the fracas, and former France star Vieira admitted he caused the tunnel chaos in an ITV documentary, Keane and Vieira: The Best of Enemies, to be screened on Tuesday.
"I started it," Vieira said. "I was cool, I was really calm, I was smiling at him - and then he lost it.
"When we played at Old Trafford his (Gary Neville's) tackling was flying in on Robert Pires and he was doing it on purpose, and I said 'listen, we are not at Old Trafford here, this is Highbury'.
"So I said to him 'if you touch Robert, I will come after you'."
Keane explained how he joined the assembled players waiting to take the pitch to find Vieira mid-flow with Neville.
"When we were going out for the start of the game I had forgotten my armband, and when I came out I had seen you at the top of the tunnel having a go at Gary," Keane said.
"What really annoyed me that night was that you were picking on Gary, you were almost picking on the weakest link, so that's what got my back up.
"There were two or three of you ganging up on Gary, simple as that."
Keane admitted he "hated" Arsenal at the peak of the sides' rivalry, which saw the two clubs win nine Premier League titles between 1995-96 and 2003-04.
"I had a lot of hatred for Arsenal because they were big rivals," Keane said.
"I can't think of any other word that springs to mind when I was going into battle with Arsenal. Hatred was the word."
Meanwhile, Vieira believes his former club's lack of leadership could ruin their bid to end a woeful run of eight years without a trophy.
Few would question the tough-tackling Frenchman's leadership qualities and Arsene Wenger's side have failed to win a major trophy since Vieira's 2005 exit.
They finally look capable of ending that barren run this season after climbing five points clear at the top of the Premier League.
However, Vieira still believes the relatively young squad would benefit from greater guidance when the going gets tough.
"I think when you look at Arsenal they play fantastic football, but you need to win games playing badly and I don't think Arsenal are capable of that at the moment," Vieira said.
"And maybe as well there is a lack of leadership. They may not have a Tony Adams, a Sol Campbell, a Martin Keown.
"These kinds of players who can be a leader on and off the field."