SLAVISA Jokanovic says Watford "will be in big trouble" if they approach their trip to The Den tomorrow with an arrogant mindset.
The Hornets are gunning for automatic promotion from the Championship and beat fellow hopefuls Middlesbrough in a crunch clash on Easter Monday.
But the view inside Vicarage Road is that Millwall will pose just as tough a test given their desperation for points at the other end of the table.
And boss Jokanovic, speaking to the Watford Observer, cautioned: "We have our battle to go up and their battle is no less than ours.
"We must be prepared and we don't have room to be arrogant and think the games in front of us will be easy.
"I expect Millwall will be motivated. They are a very aggressive team and have great team spirit and I believe they will be fighting because they need to win games to stay in the division.
"If we are arrogant in this match we will be in big trouble."