Ipswich Town are ahead against the run of play at home to in-form Millwall thanks to a strike from DJ Campbell.
The on-loan forward scored his seventh of the season five minutes before the break after meeting a cross from Aaron Cresswell.
Millwall came close to finding the target throughout the first half but Liam Trotter and James Henry were denied by a pair of brilliant saves from Stephen Henderson.
Chris Wood should have also added to his fine scoring run after 17 minutes but he missed a header from point-blank range.
Mick McCarthy's side held on in the closing minutes to take their one-goal advantage into the break.