On 23 August 2006, a match between Manchester City and Portsmouth took a dark turn when City defender Ben Thatcher knocked Portsmouth midfielder Pedro Mendes unconscious with an elbow to the head.
It was the second league match of the season for both teams, with City reeling from a 3-0 loss at Chelsea on opening day. But Thatcher, who had joined City from Leicester in 2004, had already made headlines for violent conduct after elbowing an opponent in a preseason match in China earlier that month. That player, Shanghai Shenhua's Yang Chungang, suffered a collapsed lung as a result.
Against Portsmouth at the City of Manchester Stadium, the first half was a tepid affair with neither side managing to create much of a threat. The mood quickly changed after the break, however, sparked by Thatcher's challenge. Beaten to a loose ball by Mendes near the touchline, Thatcher jumped up and swung his forearm forward, smashing his elbow into Mendes's face. The midfielder collapsed and slid into the side hoardings, then was carried off to the hospital.
The match official issued a yellow card to Thatcher, but the punishment did not end there. After reviewing the incident, Manchester City suspended Thatcher for six matches (two suspended) and fined him six weeks' wages. The FA also took action, issuing a separate eight-match ban and a suspended 15-match ban lasting two years. Mendes was released from the hospital after a day and received a written apology from Thatcher.
While that match ended as a scoreless draw, Portsmouth won the rematch at Fratton Park and finished ninth, while City ended the season five spots lower.