Millwall manager Neil Harris believes the major difference at Leeds United under Marcelo Bielsa is the mental strength the Whites have displayed this season.
Harris is preparing his Lions to welcome United to The Den on Saturday afternoon for the much-anticipated Championship clash between the two teams.
Leeds make the trip to Bermondsey unbeaten in the league with Millwall having amassed just one victory themselves this season.
The Whites are preparing for a tough afternoon in south London with Bielsa hoping to mastermind a first victory on south London soil in over six years.
Harris, who was speaking to the club's website, was questioned whether last seasons victory at home would give his side any added confidence heading into the fixture but the 41-year-old believes Leeds are a very different beast this time around.
"The players can take confidence that we are a good team with good players," Harris said.
"The first three games of the season were excellent, we got five points. The next three we haven't got a return and we should have won at least one of those games. We know when we're at our best we can compete with anyone in this league.
"What we know about Leeds is that they are a very talented side. They have a very similar group of players that they had last year and they should ultimately have cruised into the top six in my opinion and at times they were top of the league and in the top six for long periods.
"They fell away a little bit mentality wise and this year they have a new manager in who is a very experienced guy who is getting the best out of his group. What we're seeing different to last year is the mental strength in the team but we'll also still see their ability.
"It's as tough a game as we could've had."
Harris also added that his players are looking forward to the occasion: "We'll be ready for Saturday. They're going to enjoy it.
"We need the fans to come and play there part as they have done and get behind the boys. Leeds are going to have the ball and try and frustrate us but we're used to that now.
"We've got to make sure we're clinical when we have the ball and at our best."