The Gunners have won nine of their last 10 games at home in the competition but Wenger has yet to beat a side managed by Mourinho – who won back-to-back Premier League titles in his first spell at Stamford Bridge.
During that period the Frenchman endured a competitive relationship with the Portuguese manager but insists that is no longer the case, and is happy to see Mourinho return after spells at Inter and Real Madrid.
“It was not a big surprise [that Mourinho returned] because there was talk about it many times," Wenger told the club’s official website. “When he left Madrid, it looked to be one of his best opportunities to come back.
“What the Premier League wants first is the quality of the games and his teams give you always a tough game. That is what you want."
Despite previous disagreements, Wenger is happy to be reunited against Mourinho and insists the pair have moved on.
“With all competitors there are ups and downs," he added. "You could see that again yesterday between [Manuel] Pellegrini and Mourinho, because we put our whole heart into every single game.
"Sometimes we go overboard and that is part of the job. With the distance after, it always settles."
Both mangers are set to rotate with Chelsea playing its second game in three days and Wenger using the competition to give his youngsters first-team opportunities.