MILLWALL conceded twice late on as Southend came from behind to win this pre-season friendly at Roots Hall.
The Lions took the lead three minutes into the second half when a clearance hit Nathan Ralph and looped over Mark Oxley before crossing the line off the crossbar.
Southend grew back into the game as the half progressed and substitute Theo Robinson scored twice in four minutes to turn the game around.
Neil Harris' side face Real Sociedad in their last pre-season friendly on Saturday seven days before they open their Championship campaign against Preston at The Den.
Ragged first half as few players impress
Whatever it was Millwall were trying in the first half didn't work. Near the end of the half Harris could be heard imploring his players to "keep the ball".
That came after Tom Bradshaw had lost possession in midfield. Bradshaw and Jon Dadi Bodvarsson started together up front for the first time in pre-season, but they had little service and little chance to combine.
Harris is trying out various combinations and at the moment it looks like Matt Smith is a likely starter on the opening day against Alex Neil's side. No one else has really yet made a compelling case to be alongside him.
In the opening 45 minutes there was more of a likelihood of a window in the flats behind the Southend goal being broken than a ball finding the net. Ben Thompson initially did well to burst forward and dig out a shot, but his effort cleared the stand. Jed Wallace fired a free-kick from 23 yards into the second tier.
Southend were little better. Ryan Sandford gathered a low effort from Stephen McLaughlin but that was the only shot on target from either side before the break.
Millwall step it up – but suffer late lapse
The visitors were a completely different side immediately after the break, moving the ball with purpose and getting wide of Southend's defence.
Southend had barely touched the ball after the restart when the Lions worked possession to Bodvarsson and Harry Lennon was unlucky to see his attempted clearance hit Ralph and go in.
Another slick move saw Danny McNamara overlap on the right. He found Wallace inside but Oxley saved at the near post.
Millwall's defence had been comfortable but moments after Matt Smith came on for Bodvarsson Mark Milligan unleashed a ferocious shot from 35 yards that flew just over Sandford's crossbar.
Luke Hyam was next to threaten as the ball dropped to him just inside the box, and he should have tested Sandford instead of half-volleying over.
Sandford was forced into his second save in the 65th minute, but it was an easy one as Stephen Humphrys' effort was straight at him. Humphrys had another chance with 16 minutes left after playing a one-two with Charlie Kelman but the forward toe-poked wide from the edge of the box.
Humphrys' replacement Robinson made an immediate impact as he lashed into the top corner to give Sandford no chance with 15 minutes left.
Four minutes later Robinson had a second, finishing from a corner after Sandford had saved well at the near post from Brandon Goodship.
Jiri Skalak and Shaun Hutchinson had late chances, but Southend hung on.
Millwall: 4-4-2: Sandford; McNamara, Hutchinson, M Wallace, Ferguson; J Wallace (Tiensia, 88), Thompson (Mitchell, 75), Leonard, Skalak; Bradshaw, Bodvarsson (Smith, 60).
Subs: Wright, Ransom, Burey.
Image: Millwall FC