Liverpool manager Jurgen Klopp has stressed that players, rather than tactics, are a deciding factor in winning games.

The Reds are preparing to face Porto in the last 16 of the Champions League, the first leg taking place at the Estadio do Dragao in Portugal on Wednesday.

At Klopp's pre-match press conference on Tuesday, a local journalist stated that Liverpool often change their formation and could therefore be somewhat unpredictable.

The German replied by claiming that the team selection is not the key aspect on a game, instead highlighting the players' desire as an overriding factor.

"The system will never win the game," Klopp is quoted by The Mirror as saying. "It's about the players and their decision making and doing the right thing in the right moment. Throwing your heart on the pitch giving everything you have. Systems are very important but only to bring players in their best positions.

"I respect Porto a lot. They are a mixture of football and fight, experience and youth, well organised and fluent. I like it. But to be honest, they've not played 20 times against a team like us. We are not too bad and we know that as well. We want to show it and use it, and we will see tomorrow night and in two weeks. I know it's a close race, no problem with that."

Liverpool, Champions League winners in 2005, are aiming to reach the quarter-final stage of the competition for the first time in nine years.