Few fixtures divide loyalties quite like a Merseyside derby. At least twice a season, families become split and friendships are placed on hold whenever Liverpool and Everton do battle.
Conditioning coach Jan Kluitenberg learnt at first-hand the perils of having companions behind enemy lines in this biannual duel for points and bragging rights.
During a 16-month spell with Everton, Al Jazira’s current head of conditioning was afforded a touchline view of Sadio Mane pouncing in the 94th minute to win a cagey derby encounter for Jurgen Klopp’s side in December 2016.
The Senegalese forward was already familiar to Kluitenberg from their time together at Southampton.
That intimate knowledge, just months before finding themselves on opposing sides of Stanley Park, made Mane’s late sucker-punch, an already bitter pill for his former fitness coach, even more difficult to stomach.
“Of course I remember the goal, very late in the game,” Kluitenberg said.
“We didn't play that bad, I think. But before the game, Mane already was always a little bit smiling and a funny boy. He said, 'It would be nice if I score one goal against you'.
“Typically, sometimes things happen in football like this. He scored and we were very disappointed. I was also very disappointed, of course, for the fans. It was really difficult to shake his hand, but we did.
“You need to take your loss but it felt maybe a little bit more edgy because we had a great time with him, and the fans expect a lot more from us against Liverpool.”
Kluitenberg, 59, may be observing Sunday’s 240th showdown at Anfield from a distance but he does so with keen interest.
His affection for Everton and its supporters remains strong despite the rapid decline of Ronald Koeman’s tenure, barely a year after Mane had snatched the spoils.
But it is another of Kluitenberg’s erstwhile colleagues from the south coast who also attracts his attention in Virgil van Dijk.
The Netherlands defender, who will face Mane’s Senegal in November’s World Cup opener, suffered a season-ending knee injury in last season’s Goodison stalemate after a collision with Toffees’ goalkeeper Jordan Pickford.
Liverpool’s Premier League title defence unravelled as an indirect consequence of his absence, while the Netherlands failed to progress beyond the group stage at Euro 2020.
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As a proud Dutchman, who also worked with Van Dijk for their national team, Kluitenberg has been impressed by the speed with which he has reacclimatised for club and country.
“If you come back from an ACL you are, let's say, nine months out,” he said.
“Then you need to make steps well. I know the medical staff at Liverpool [are] high quality and the more games you play on the pitch, you should be ready.
“But I think also if you play the games, you need some time to come back. He's showed at Liverpool and with the national team that he is back on the level where he was.”
Everton return to their one-time home Anfield this weekend with memories of last February’s long-awaited victory there fresh in the mind but now superseded by a target of top-flight survival.
That bid is likely to go down to the wire with Frank Lampard’s side facing an unenviable run-in against opponents at both extremes of the Premier League table.