Raymond Verheijen, the professional coach who has often attracted headlines for slamming the training methods of various managers on Twitter, has been at it again.
This time, Liverpool boss Jürgen Klopp was the target of his ire, after the Reds' sputtering performances in recent matches - a far cry from the team's impressive early-season form.
So, what exactly is Verheijen blaming for the Merseysiders' faltering showings as of late?
Is Klopp guilty of "destroying players"?
Liverpool were knocked out of the EFL Cup on Wednesday, suffering a 1-0 defeat in their semi-final second leg fixture and losing 2-0 on aggregate. In fact, of the seven games they have played in January, they have lost three and drawn three - their sole victory coming in their FA Cup third-round replay against League Two minnows Plymouth.
In a series of tweets, Verheijen questioned why there was widespread surprise at Liverpool's poor performances in what has so far passed of the season's second half. He insisted that this slump had been predicted in pre-season - likely a reference, at least in part, to his own claims last July, reported by Football365, that Klopp's training methods were "destroying players" and from "30 years ago".
Still, his words didn't come across as entirely publicity-seeking. Verheijen, who is director of the World Football Academy, said that Klopp, who previously built a league- and cup-winning team at his former club Borussia Dortmund, remained one of the world's best managers. However, he insisted that "he clearly has some flaws in his pre-season training methods. Raise your bar!"
Klopp hits back at "this Dutch guy"
Verheijen, who often uses his Twitter account as a portal for his opinions, has been a coach/consultant at every World Cup and EURO tournament this century. However, we shouldn't expect Klopp to react pragmatically to this fresh sting from such a long-standing critic, whose nickname of "fitness egg" comes from his inconspicuous Twitter avatar.
In October, the German ridiculed fixture planners for scheduling Liverpool's festive matches in an "unbelievable" way. A home match with Manchester City had been shifted to 5:40pm on New Year's Eve, which gave Liverpool less than 48 hours in which to prepare for the following clash with Sunderland, which was scheduled for 3pm on 2nd January.
He explained, as quoted by the Daily Mail: "I'd never say Boxing Day is not a good idea. But having a match day with two days in-between? There should be another possibility. 48 hours between two games? How does this work?" He added that, afterwards, the press "will sit there and say 'you didn't perform too well, how did this happen?' or 'Injuries. Oh?'"
In a thinly-veiled dig at Verheijen in particular, he continued that "then this Dutch guy says 'The training is not too good'. How do you prepare a team for this?"
Verheijen makes a counter-attack
That sly attack obviously wasn't subtle enough to escape Verheijen's notice. The former assistant manager of Wales under Gary Speed returned to Twitter with a retort that Klopp was unduly blaming "external factors". And he made a direct reference to the "Dutch guy" comment...
First blood to Verheijen, then - but this fight could have a few more rounds yet.