Arsene Wenger still remembers previous meetings with Sam Allardyce, and "very cruel" results, as Arsenal prepare to face Crystal Palace in the Premier League.
Allardyce was named Palace manager on December 23, replacing Alan Pardew, and his second match in charge is a trip to the Emirates Stadium on Sunday.
Wenger recalls numerous battles with Allardyce, including a 2-2 draw at Bolton during the 2002-03 Premier League season.
Those dropped points would prove costly for Arsenal, who finished second to Manchester United, while Bolton managed to avoid relegation.
"Of course, I remember the 2-2 at Bolton," Wenger told UK newspapers.
"Football is like real life but in a more condensed way, more intense. At some moments it catches you suddenly and it can be very cruel.
"In competition it is like that."
Wenger was full of praise for Allardyce, who is back in management after his ill-fated one-game stint as England boss.
Allardyce's first game in charge of Palace resulted in a 1-1 draw at Watford.
"He has the quality of a guy who is intelligent as he adapts to the level of his team and makes it simple for them to apply what he wants," Wenger said.
"So I believe adaptability is one of his strengths."