Mark Beevers struck inside the opening 10 minutes to set Millwall on their way to a 2-0 victory over Leeds and their first opening-day win since 2010.
The Lions, without a victory to kick off their Championship season at the last three attempts, welcomed Leeds - under new boss Dave Hockaday - to The Den.
Beevers got them off to a flyer after a neat short corner routine and Shaun Williams made sure of the result from the penalty spot two minutes from time.
In the opening stages neither side looked likely to score as they started restlessly, both struggling to gain possession and cautiously testing one another.
But Millwall carved out an early breakthrough, catching Leeds' back line off guard with a short corner and allowing Beevers to put them ahead in the eighth minute.
Following a neatly-worked move, the defender stretched beyond his marker and turned Lee Martin's cross into the net past the rooted Marco Silvestri.
The goal settled any nerves the home side had and they continued to press forward, now in search of a second, with Scott McDonald at the heart of all their endeavours.
Ian Holloway's men could have doubled their lead 10 minutes later through Beevers again, but he was unable to make the most of his free header, turning it wide.
It was a half of few chances and the home fans encouraged their team to shoot whenever possible.
However, only two sides conceded more Championship goals than Millwall men last season and the majority of the Lions' support was content to see them preserve both their clean sheet and a lead into the break.
Leeds nearly drew level soon after the break when Millwall goalkeeper David Forde made a mistake rushing to the ball, which fell kindly to Nicky Ajose.
He picked out Noel Hunt in the centre of the box, who sent a low strike but Carlos Edwards was on the line to clear away to safety.
The hosts then rushed down the other end where Martyn Woolford saw his shot saved by Silvestri in a frantic opening few minutes to the second half.
Edwards was then brought down just to the right-hand edge of the Leeds area but Williams could not convert the free-kick, his tame shot easily taken by Silvestri.
Millwall looked to have a penalty on 57 minutes when Martyn Woolford was brought down but Oliver Langford waived protests away and Leeds broke but to no avail.
However, the hosts put the game beyond doubt in the closing moments of the match when substitute Lee Gregory, making his debut, was fouled in the area by Lewis Cook.
Williams stepped up stuck the resulting penalty to Silvestri's right and into the back of the net.