On-the-whistle-report: Rotherham United 0 Millwall 1

The promoted Millers were the better side against a team that finished close to a play-off spot last season but fell to defeat after disaster struck in the 50th minute.

Michael Ihiekwe, the club's most consistent player for the last 12 months, uncharacteristically let the ball squirm under his foot and unwittingly set up Jed Wallace to score the decisive goal.

Both teams started in combative fashion but it was Rotherham who looked the most dangerous.

Chances were hard to come by until the 20th minute when Wes Harding freed Chiedozie Ogbene down the right. The winger's low ball in found Freddie Ladapo only for the home striker to direct an inviting opportunity wide.

Six minutes later, Scott Malone fired a 20-yard free-kick over the bar as the visitors had their first clear sight of goal following Ihiekwe's foul on Mason Bennett.

However, the impressive Millers were exerting pressure on Gary Rowett's side and Kieran Sadlier dragged a shot off target from a corner on the half-hour mark.

Rotherham could have gone in at the break 1-0 up but Michael Smith got his timing wrong with a header from Wes Harding's cross on the stroke of half-time.

Boss Paul Warne had dropped midfielder Matt Crooks to the bench, bringing in Smith to partner Ladapo up front.

Centre-half Angus MacDonald came in for his debut in place of the injured Clark Robertson while there were substitute spots for captain Richard Wood, back after a back complaint, and new boy George Hirst.

The game changed five minutes after the interval when Ihiekwe produced his rare blunder.

The centre-half, who was so assured throughout last term's League One promotion campaign, let the ball slip through him, allowing Jed Wallace in on goal.

Goalkeeper Jamal Blackman made life easy for the Millwall midfielder by running out and committing himself too early and the subsequent tap-in into a gaping net was simple.

Wallace could have doubled the Lions' advantage on 59 minutes but shot just past the post.

The Millers responded with a header from MacDonald and a Joe Mattok shot that both required saves from Bartosz Bialowski and then brought on Hirst for his debut taste of action at AESSEAL New York Stadium.

The loan striker's first effort on goal came within four minutes of his 66th-minute arrival but his fierce shot was blocked.

Rotherham pushed hard as full-time approached but could find no way through.

Goals: Wallace 50 (Millwall).

Rotherham (4-4-2): Jamal Blackman; Wes Harding, Michael Ihiekwe, Angus MacDonald, Joe Mattock; Chiedozie Ogbene, Shaun MacDonald, Jamie Lindsay (Matt Crooks 76), Kieran Sadlier (Ben Wiles 66); Freddie Ladapo (George Hirst 66), Michael Smith. Subs not used: Viktor Johansson, Richard Wood, Mickel Miller, Kyle Vassell.

Millwall (3-5-2): Bartosz Bialowski; Shaun Hutchinson, Alex Pearce, Jake Cooper; Mahlon Romeo (Shaun Williams 74), Ryan Leonard, Ryan Woods, Jed Wallace, Scott Malone  (Murray Wallace 74); Tom Bradshaw, Mason Bennett (Matt Smith 82). Subs not used: Joe Wright, Shane Ferguson, Connor Mahoney, Jon Dadi Bodvarsson.

Referee: Leigh Doughty (Blackpool).