Dejan Lovren's assertion that when it comes to Liverpool's challenge in this season's Premier League title race, "our biggest opponent is us" was encapsulated in his internal battle during two first-half minutes when his headed goal redeemed a mistake moments earlier that had gifted Crystal Palace an equaliser. The Croatian centre-back's personal experience reflected that of manager Jürgen Klopp's side; impressive going forward yet remaining vulnerable defensively.Klopp, though, insists he is confident in his side's defensive qualities while Lovren's reaction to his own error in slicing a back-pass into the path of Palace midfielder James McArthur - who also out-jumped the Liverpool defender for a second equaliser - pointed to a resolve within the team essential for any side hoping to sustain a challenge at the head of the table."I was angry. I was definitely angry," said Lovren. "The lads asked me in the dressing room, 'what did you want to do when you scored the goal?' I said I wanted to jump into the crowd."He added: "When you have a winning team you have to have your character and to move on quickly and I think we showed that today [on Saturday], especially in the first half after the mistakes."But I think we have shown this year that we can play against the big teams, we are not scared. I think the biggest opponent for us is us."Klopp's faith in his back-four may remain, but he is also aware that his side's strengths lie further forward, where Philippe Coutinho - described by Lovren as the league's best player right now - Roberto Firmino, Adam Lallana and Sadio Mané ensured that the Reds recovered after McArthur's goals cancelled out Emre Can and Lovren's efforts.Defender Joel Matip headed the third immediately before half time and Firmino added a second-half fourth.His team are rarely less than entertaining but Klopp said: "We don't play this way because we want to show something, we do it because it helps us, because the best kind of defending is keeping the ball."What makes less sense to the manager is the claim that, in addition to strengths of his squad, their absence from Europe this season gives them an advantage over their rivals."I know everyone talks about this, but I think in 80% to 90% of leagues in Europe, the teams becoming champions are in the Champions League. That's how it is," said Klopp."Why? Because they have quality, they can rotate, they can rest whenever.It's not too cool when you are not successful."Like Klopp, Palace manager Alan Pardew was forced to reflect on a performance of chaotic defending that, in his side's case, led to a third successive defeat.Next weekend's trip to Burnley takes on more significance and will pose a different kind of test but McArthur said: "We need to work on our defensive play this week, and not conceding is a big thing for us."More and more pressure is on us with each game we don't win. I know pressure is part and parcel of being a footballer, but one win changes everything and kicks you on..." ..