Coutinho made his first Premier League start since November after recovering from a knee injury.
However, the Reds found themselves 2-0 down to the away side at Anfield early in the second half before Roberto Firmino reduced the deficit.
Liverpool fans clash on Twitter over Jurgen Klopp after Swansea defeat
Sun, January 22, 2017
Liverpool fans have clashed on Twitter over manager Jurgen Klopp after the Reds slipped to a 3-2 defeat against Swansea City yesterday
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Liverpool fans clash over Jurgen Klopp and his tactics after the Reds slipped to a 3-2 defeat against Swansea
Klopp then opted to take off his Brazilian playmaker and replace him with Daniel Sturridge.
Firmino levelled the match with a stunning half-volley but Liverpool's title hopes suffered a blow when Gylfi Sigurdsson restored Swansea's lead and earned them a precious win late on.
Liverpool’s Philippe Coutinho in action with Swansea's Kyle Naughton
Liverpool manager Jurgen Klopp hugs Philippe Coutinho after he is substituted
And Klopp says he took off Coutinho to protect him after coming back from injury.
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He said: "That is how it is. You could force it and say ‘come on, come on, you need to go through it'.
Philippe Coutinho was replaced by Daniel Sturridge
"But even in a situation when you are 2-0 down when you've decided we need to change things, we are really serious about things like this.
"Sometimes we have had a problem and we've had to force players to come through the games, but really here with him it makes no sense."