After winning the competition last season and currently dominating the Premier League, the Reds are seen as strong favourites ahead of their round of 16 tie against Atletico Madrid.
Gomez however stressed the side aren't letting their success impact how they approach matches as he suggested they view themselves as underdogs ahead of the first leg in Spain.
"It’s just about establishing yourself. You aren’t proven winners until you show you can do it again and again," Gomez said.
"We went [to Madrid] last season and beat Spurs in one game. Now it is about maintaining that reputation in the Champions League.
"People might say, 'Oh yeah, they’re performing well', but as a team we have still got an underdog mentality.
"We’ve won the Champions League, but everyone is eager to win it again. The focus within the camp is just one game at a time. It comes right from the gaffer through the spine of the team — the skipper [Jordan Henderson[ and Milly [James Milner]."
Liverpool will return to the venue where they won the Champions League final last season on Tuesday night and Gomez is confident the Reds won't let those fond memories distract them on the pitch.
"Look, it’s just a venue," Gomez replied when asked about playing at the Wanda Metropolitano again.
"It’s a pitch with four white lines and two goals. You could say the same about Anfield. We have had loads of good games there, too. You can’t correlate last June to playing Atletico.
"It doesn’t need saying to anyone in the team. That’s what is making this such a pleasant journey. We just keep going forward."
Jurgen Klopp's side most recently beat Norwich City 1-0 - a result that all but secured their place in the Champions League next season.
The Reds have won all but one of their 26 matches in the Premier League this season and are currently 25 points clear of second-placed Manchester City.