Liverpool's throw-in coach Thomas Gronnemark has responded to sneering criticism from Steve Nicol with a thinly-veiled tweet.
A video of former Reds defender Nicol arguing about the merits of the Dane's coaching went viral on Friday due to the heated nature of the Scot's debate with football journalist Julien Laurens.
In the ESPN clip, Nicol roundly dismisses the work of Gronnemark after the Reds scored the winning goal at Wolves on Thursday night moments after a throw in around the 84th-minute mark.
"Because it came from a throw in, it's 'well done the throw-in coach because you know what? If we didn't have the throw-in coach, that would never have happened...'" said Nicol.
"I mean who did they blame when Trent Alexander-Arnold whipped in that corner for Divock Origi against Barcelona? Was that a corner coach was it? Absolute nonsense.
"By the way, can anybody tell me, seriously, what qualifications do you need? How much do they pay that coach? Too much."
The view was challenged by French reporter Laurens who talked up Gronnemark's success at FC Midtjylland and beyond before Nicol scoffed further.
Nicol's attitude to that particular area of coaching came under fire across social media with many believing his school of thought belonged to a bygone era in football.
Gronnemark responded on Twitter on Saturday, but refused to publicly call out or condemn the ESPN pundit as he offered a measured tweet about general criticism.
"TWO kinds of CRTI(C)ISM!" posted the Liverpool coach.
"THE CONSTRUCTIVE - where people are suggesting potential improvement based on knowledge, and make people or projects grow
"THE DESTRUCTIVE - where people are criticizing from an uninformed position, or do it because of self promotion
"what do you choose?"
Gronnemark was personally headhunted by Klopp to come and work at Melwood part time in 2018 after the Reds boss decided too much possession was being squandered from throw-ins.
Since the Dane joined on board as part of the coaching staff under Klopp, Liverpool improved to the point where they retained possession from throws under pressure 68.4 per cent of the time dating back to the start of the current campaign.
That figure was the best in the Premier League at the time and the most impressive of all but one club in Europe - Gronnemark's own, FC Midtjylland. The 44-year-old recently took on a similar role with Dutch giants Ajax.