Gary Rowett enjoyed the perfect start to his time in charge of Millwall with a 2-0 win over former club Stoke.
Ben Thompson's first goal of the season set the home side on their way before Jed Wallace's penalty 15 minutes from time secured all three points.
Stoke threatened to spoil the party in the second half, but Millwall defended doggedly for long periods before striking on the counter-attack.
Rowett was sacked by Stoke in January, when they sat 14th in the Championship, but on his return to management found his former club mired in the relegation zone.
And the Potters showed why they have struggled so badly this season, with a performance desperately lacking in quality.
Millwall, for their part, did not look radically different from the solid side built by Neil Harris, and they struggled to get out of their own half for large parts of the second half, but Rowett will have been pleased with how few chances his new side allowed his old.
The home side started the brighter, with both Jed Wallace and then Murray Wallace cutting in from the left to curl 20-yard shots narrowly past the far post.
On the half-hour mark Millwall's superiority was finally rewarded, Thompson adjusting his feet excellently to volley Jed Wallace's cross into the corner of the net.
Shaun Hutchinson had a great chance to double the lead five minutes later, when Stoke failed to properly clear a corner, but could not get any power on his header allowing Adam Federici to save easily.
Stoke, for their part, offered next to nothing. Their only shot of the first half came from Badou Ndiaye's 30-yard effort, which skimmed harmlessly wide, while Scott Hogan and the returning Lee Gregory – back at the Den after leaving Millwall in the summer – scarcely got a kick.
Nathan Jones introduced James McClean at half-time for the visitors and he added some forward thrust – but it was Gregory who should have equalised, somehow prodding wide from six yards when Tom Ince's cross landed at his feet.
Yet despite dominating possession and territory after the break, Stoke could not muster a single shot on target until the 87th minute – and even that was a tame header straight at Bartosz Bialkowski.
At the other end Millwall continued to create chances, with Jed Wallace forcing Federici into a fine save one-on-one before his brilliant, jinking run on the counter decided the contest.
Wallace escaped two defenders on the halfway line despite being fouled, skipped past another and then forced Ndiaye into a poor challenge in the box.
Referee Darren England had no hesitation in pointing to the spot, and Wallace picked himself up to smash the penalty home and ensure Rowett an opening win.