Benik Afobe’s 16th minute goal sees Millwall lead the Blues 1-0 at half-time at the Den.
Marcus Harness was handed his first appearance for the Blues as one of the number 10s behind striker Freddie Ladapo to the left of Conor Chaplin in a team probably not far off the XI which will start against Bolton Wanderers in next Saturday’s opening League One match at Portman Road.
Janoi Donacien, Luke Woolfenden and George Edmundson were the back three with Wes Burns and Matt Penney the wing-backs. Greg Leigh was not in the squad, suggesting the former Morecambe man may have picked up a knock.
Skipper Sam Morsy and Lee Evans were the central midfield pairing with Dominic Ball also absent, while Kyle Edwards is back in the squad having missed the last couple of friendlies with a niggle.
Christian Walton was in goal for the Blues with former Town goalkeeper Bartosz Bialkowski between the sticks for Millwall.
The game got off to an evenly-balanced start with both sides giving the ball away more than they would have wanted, but as the 10-minute mark approached the home side began to threaten, Zian Flemming shooting over on nine.
And in the 16th minute the Lions took the lead. Woolfenden was caught in possession playing it out from the back on the edge of the box to the right Afobe brought the ball in on goal before shooting confidently past Walton.
It was a poor goal for Town to concede and not the first during pre-season to come as a result of the Blues being dispossessed as they played it out from the back.
Town, wearing their black and red away kit for the first time, threatened for the first time in the 24th minute, Donacien whipping a cross in from deep on the right and Ladapo flicking a header well wide of Bialkowski’s right post.
Three minutes later, following a drinks break, Town broke forward having picked up a loose pass on halfway and the former Rotherham man hit a low shot to Bialkowski’s right which the Polish keeper claimed with little fanfare.
As the half hour approached, the Blues began to see most of the ball but without creating any opportunities or testing Bialkowski.
On 38 Burns shot against a defender after a looping Evans cross from the right had fallen to him in the area, then Penney screwed the loose ball well into the empty stand behind the goal.
A minute later, Woolfenden got a toe in ahead of George Honeyman as a cross came in from the left after Millwall’s pressing had led to the Blues lose possession not far outside their own area.
In the 44th minute, the Blues worked the ball well on the left and Chaplin hit a low shot across the face of goal from a tight angle.
That was the last action of a half in which the Blues had seen a lot of the ball and had played some neat and tidy football at times but without being able carve out any serious opportunities.
At the other end, the goal came from perhaps a little over-confidence from Woolfenden and other than that Walton had had as quiet an afternoon as Bialkowski.
New boy Harness had often dropped deep to pick up the ball and had shown one or two neat touches but without finding a pass which might open up the Millwall defence.
Millwall: Bialkowski, Wallace, Hutchinson, Cooper, Afobe, B Mitchell, Flemming, Malone, Shackleton, Leonard, Honeyman. Subs: Long, McNamara, Evans, Bradshaw, Burey, Cresswell, Bennett, Saville, Topalloj.
Town: Walton, Donacien, Woolfenden, Edmundson, Burns, Evans, Morsy, Penney, Chaplin, Harness Ladapo. Hladky, Burgess, Ndaba, Vincent-Young, El Mizouni, Harper, Humphreys, Aluko, Edwards, John-Jules, Jackson. Referee: Gavin Ward (Surrey).