Frank de Boer reignited his war of words with Jose Mourinho, stating that he believes "karma always strikes back".
De Boer and Mourinho's rivalry began when the former was the manager of Crystal Palace and criticized the latter's handling of Marcus Rashford during his tenure as Manchester United manager, saying that it was "a pity that the manager is Mourinho".
The Portuguese boss fired back soon after, labelling de Boer the “worst manager in the history of the Premier League”.
De Boer's stint at Crystal Palace was historically poor, with the club earning zero points while scoring zero goals in his four matches before his September 2017 sacking.
Mourinho snuck in a further jibe at that fact, stating that, if the Dutchman was Rashford's manager, he "would be coached how to lose because he lost every game".
And now, more than a year and a half later, De Boer has fired back while defending his Palace tenure.
“At that moment, he can say that because it was a really bad record, of course,” De Boer told the Guardian.
“For me, if he wants to say that, I’m not the guy who wants to respond to that … I think karma always strikes back.”
Following his Palace departure, De Boer's reputation took a hit, especially when factoring in a failed tenure at Inter that lasted just 85 days.
Prior to those stints, De Boer had found success at former club Ajax, winning the league four times.
“I’m convinced,” he said. “I think if we get the time we should, we definitely turn it around, especially at Crystal Palace. We had a feeling, in training you saw it, that this is the moment we’re going to go looking up and win games. And then they decided to sack me. Of course that’s not the nicest feeling, but it’s like that.”
He added: “I was especially angry. They do some promises and they have a philosophy: ‘OK, we want to be a solid club.’
"For example, Crystal Palace, you have to also play like a modern team and don’t play relegation football. If you want to do that, OK, one year you can survive, maybe two years. But one time you will go down, I am convinced.
“So they wanted to change that, like Southampton was doing in that period. I saw that picture in front of me, so I had the feeling that I had time, but when the season started, you already see some signs that this is not the way.
"You always walk in front of a door, and it’s not opening, and I had the feeling again, and also at Inter, that we have to do this and this, and then we make our steps forward. Every time somebody was stepping on the brakes.”