Liverpool secured a big win, but Klopp has reasons to worry as Diogo Jota, Curtis Jones, and Darwin Núñez all got injured in the first half. Are more injuries on the way? That's the main concern. It won't be easy, but Liverpool need to keep pushing and hoping for the best.
With just 5-point lead at the top of the Premier League, Liverpool could end up just 1 point behind the top spot if Man City win their two games in hand. I sees Man City will win those matches.
Winning with a pretty fantastic score certainly made Klopp happy and Liverpool also celebrated when Liverpool were able to beat Brentford. However, if Liverpool is experiencing an unfortunate fate such as the injuries to the three players you mentioned, of course this is a big worry for Liverpool, who at this time can still be a candidate to win the Premier League. Klopp must be able to handle this well in the next few matches because considering that these three players are players that Klopp has relied on very often this season.