And after just over an hour Klopp changed his mind and performed a dramatic swap with dramatic results.
"It's one thing it coming from the manger's mouth - there being a feeling that he shouldn't be sold - but now they are in a situation that sets a precedent for future deals".
Liverpool dominated the game throughout and fashioned a number of good openings, relief around the ground finally being brought about as Mane latched onto a loose ball to fire past Wayne Hennessey in the Palace net.
And at free kicks too Coutinho's absence was felt more than ever when Palace were there for the taking.
FW Sadio Mane, 7 - While Coutinho may be Liverpool's most talented player, Mane is their most important.
MF Jordan Henderson, 7 - Didn't quite have his radar working in the first half and some of his passes were a little off, but the skipper was diligent in his work protecting the defence and snuffing out potential counterattacks.
But Palace had chances of their own - the best falling to Christian Benteke as he blazed over from close range in the first half - and the Dutchman says he is confident of success if they show this spirit each game.
Adam Lallana also misses today's encounter with Palace.
And he was joined in the directors' box by England manager Gareth Southgate.
Liverpool boss Jurgen Klopp has made five changes for today's Premier League clash with Crystal Palace, and unsurprisingly, Dejan Lovren is one of the players dumped on the bench. "I have no idea how much we had the ball but it was a lot", he said. We already have a team which I like and could play football with.
Mohamed Salah was introduced on the hour and the Egyptian made a massive impact, using his pace and surprising strength to help Liverpool find the edge that was missing in the first half.
It could be considered a lucky goal, but Klopp has always spoken of his teams' ability to create chances through counter-pressing even when they don't have possession.
"When there is no other decision possible - on the 31st of August - then we have to think about everything new".
"We can only play one way and that is forward".
"We have to fight every minute together".
"This time I knew I was ready, I knew about the Premier League and how competitive it was", the former Inter coach said.